Photosensitive resin composition and photosensitive films and laminates made by using the same

ABSTRACT

A photosensitive resin composition of the present invention contains a (A) soluble polyimide and a (b) (meth)acrylic compound, the (A) soluble polyimide being soluble in an organic solvent and being synthesized by using an acid dianhydride component and at least one of a diamine component containing a siloxane structure or an aromatic ring structure, and a diamine component having, in its structure, a hydroxyl group a carboxyl group or a carbonyl group, and the (B) (meth)acrylic compound having at least one carbon-carbon double bond, and preferably contains at least one of a (C) photo reaction initiator and a (D) fire retardant. With this arrangement, the photosensitive resin composition of the present invention is capable of having excellent properties. Especially, the photosensitive resin composition of the present invention is so excellently useful that it can be used for electronic parts and the like.

TECHNICAL FIELD

[0001] The present invention relates to (a) a photosensitive resincomposition having a polyimide, (b) a photosensitive film in which thesame is used, and (c) a laminate in which the same is used. Especially,the present invention relates to (d) a photosensitive resin compositionwhose light exposure can be performed by using an ordinary lightexposing apparatus, the photosensitive resin composition containing apolyimide-based resin and a (meth)acryl-based compound, (e) aphotosensitive film and a laminate that are produced from thephotosensitive resin composition, and that are employable as aphotosensitive cover lay film or photosensitive dry film resist.

BACKGROUND ART

[0002] As a result of rapid developments in electronic devices in recentyears, the electronic devices have become more sophisticated infunction, able to work with high performance and yet downsized. Inaccordance with this, electronic parts are required to be downsized andlighter in weight. For this reason, in terms of wiring boards on whichthe electronic parts are mounted, flexible printed wiring boards(hereinafter, abbreviated as FPCs) that have flexibility, draw attentionthan ever before, compared with generally-used rigid printed wiringboards. Thus, demand for FPCs rapidly is increasing recently.

[0003] Incidentally, most of FPCs are produced from a copper-cladlaminate (CCL). On a surface (conduction surface) of such an FPC havinga CCL, a circuit (pattern circuit) is uncovered, which is made of copperand patterned in a predetermined pattern. There is a possibility thatthe pattern circuit thus uncovered is deteriorated. Thus, a cover layfilm (insulating protective film) is layered on the surface. The coverlay film also has a function to attain better flexibility.

[0004] As a method of layering the cover lay film on the surface of theFPC, the following method is generally used: first, the cover lay filmis processed into a predetermined shape, and an adhesive layer is formedon one surface thereof; the cover lay film is placed on the FPC withaccurate positioning; then, the cover lay film is thermocompression-bonded on the FPC by pressing or the like.

[0005] However, in the generally-used method, an epoxy adhesive agent,an acrylic adhesive agent, or the like is used popularly. Some of thoseadhesive agents have low heat resistance property such as soldering heatresistance, adhesive strength when subjected to a high temperature,whereas the others are poor in flexibility. Thus, there is a problemthat use of those adhesive agents prevents full utilization of propertyof a polyimide film used as the cover lay film.

[0006] Moreover, in case where the cover lay film is processed into apredetermined shape before layering, it is necessary that the cover layfilm have a hole or a window in such a position that corresponds to ajunction section of the pattern circuit on the surface of the FPC, thejunction section being a section to which a terminal section or variousparts are to be jointed. However, it is difficult to form a hole or thelike in the cover lay film that is so thin. Further, the hole or thelike of the cover lay film is almost manually positioned with thejointing part for the terminal section. Thus, it is a problem that suchmanual operation reduces not only workability in layering the cover layfilm on the FPC, but also accuracy in positioning, and further suchmanual operation leads to a high cost.

[0007] Furthermore, as a method other than the method in which the coverlay film is processed before layering, known is a method in which thecover lay film is processed by etching after layering. To explainspecifically, a hole, a window, or the like is formed in a predeterminedposition of the cover lay film by laser etching, plasma etching, or thelike method, after the cover lay film is adhered to the FPC by thermocompression bonding. This method improves accuracy in positioning.However, it is a drawback of this method that the formation of the holeor the window in this method takes a long time and requires an expensiveprocessing apparatus and a higher production cost.

[0008] Use of a photosensitive resin composition is known as an art tosolve the problems. Specifically, the photosensitive resin compositionis used as follows:

[0009] (1) photosensitive resin composition is applied on a surface ofan FPC so as to form a resin layer thereon and to use the resin layer asthe cover lay layer; or

[0010] (2) a photosensitive film produced in advance is layered on asurface of an FPC, then exposed to light and developed with a photomaskused, so as to form a resin layer thereon and use the resin layer as acover lay layer.

[0011] Moreover, besides the formation of the cover lay layer, anotherusage of the photosensitive film is to use the photosensitive film as afilm-like shaped photo resist for use in forming, by etching copperfoil, a circuit made of copper. In this case, the photosensitive film ispeeled off from a printed wiring board or the like after used as a photoresist for the etching.

[0012] In the use of such photosensitive resin composition, it ispossible to utilize the photosensitive resin composition as the photoresist in exposing and development the resin layer layered on thesurface of a CCL on which a circuit is formed. Thus, it is possible toform a hole or a window highly accurately in a predetermined position ofthe CCL. Furthermore, it is possible to use the resin layer as the coverlay film, by, if necessary, thermally curing the resin layer thereafter.To sum up, the photosensitive cover lay film can be used, not only as aninsulating protective film, but also as the film-like shaped photoresist (photosensitive dry resist film). This makes it possible toimprove workability and accuracy in positioning.

[0013] Especially, the use of a photosensitive cover lay film of dryfilm type gives the following advantages compared with the method inwhich the photosensitive resin composition is applied: the use of thephotosensitive cover lay film of dry film type eliminates labor and timefor applying and drying; and a large number of holes can be formed atonce by developing the photosensitive cover lay film of dry film type.Thus, it is possible to manufacture the FPCs more efficiently.

[0014] However, the photosensitive resin composition and thephotosensitive cover lay film are produced from (meth)acrylic typeresin, generally. For example, photosensitive cover lay films whose maincomponent is commercially available (meth)acrylic type resin, are known,which are disclosed in Japanese Publications of Unexamined PatentApplications, Tokukaihei No. 7-278492 (published on Oct. 24, 1995),Tokukaihei No. 7-253667 (published on Oct. 3, 1995), Tokukaihei No.10-254132 (published on Sep. 25, 1998), Tokukaihei No. 10-115919(published on May 6, 1998) and the like.

[0015] Moreover, apart from the (meth)acryl type resin, a photosensitivecover lay film whose main component is epoxy type resin is also known,for example.

[0016] However, those photosensitive cover lay films have such problemsthat the photosensitive cover lay films are, after curing, inadequate insoldering heat resistance, folding resistance (frangibility, flexingresistance), chemical resistance, electric insulating property, flameresistance, and the like. There has been a demand for improvement ofthose photosensitive cover lay films.

[0017] In view of this, arts in which a resin composition containing thephotosensitive polyimide is used have been conventionally developed inorder to solve the problems.

[0018] Specifically, for example, photosensitive polyimides into which amethacryloyl group is introduced via an ester bonding are disclosed inJapanese Publications of Patents, Tokukousho No. 55-030207 (JapanesePublication of Unexamined Patent application, Tokukaisho No. 49-115541,published on Nov. 5, 1974), and Tokukousho, No. 55-041422 (JapanesePublication of Unexamined Patent application, Tokukaisho No. 51-40922,published on Apr. 6, 1976).

[0019] Moreover, in Japanese Publications of Unexamined PatentApplications, Tokukaisho No. 54-145794 (published on Nov. 14, 1979),Tokukaisho No. 59-160140 (published on Sep. 10, 1984), Tokukaihei No.03-170547 (published on Jul. 24, 1991), Tokukaihei 03-186847 (publishedon Aug. 14, 1991), Tokukaisho No. 61-118424 (published on Jun. 5, 1986),disclosed are photosensitive polyimides in which (a) an amine compoundhaving a methacryloyl group, or (b) a diisocyanate compound isintroduced at a position of a carboxyl group of a polyamic acid.

[0020] However, production of the photosensitive polyimides disclosed inthose publications needs imidization of a polyamic acid after exposureto light and development. Therefore, there are (1) heat-causingproblems: it is necessary to apply a temperature of 250° C. or higher onthe FPCs. In general FPCs, application of a high temperature of 250° C.or higher changes crystalline structure of copper thereby deterioratingthe circuit made of copper, and (2) problems associated with theimidization: some photosensitive polyimides require removal of anacryloyl group by heat, and the removal of the acryloly group causessignification reduction of film thickness.

[0021] Incidentally, besides being layered on the FPC, thephotosensitive cover lay film is layered, for example, on a head sectionof a hard disc apparatus, and the like. The hard disc apparatus is usedwidely in personal computer and the like. To be used as such in thoseelectronic parts and the like, a flame resistance is required for fearof inflammation due to long-time exposure to the electronic parts to ahigh temperature. Thus, the photosensitive cover lay film should have ahigh flame resistance.

[0022] As an art that also attempts to improve the flame resistance,Japanese publication of Unexamined Patent Application, Tokukai,2001-335619, (published on Dec. 4, 2001) discloses a photosensitivecover lay film in which an epoxy-modified polyimide is used. Thephotosensitive cover lay film disclosed in the publication hassufficient heat resistance, chemical resistance, and folding resistance.However, the photosensitive cover lay film shows a poor fluidity duringthermo compression bonding. Thus, it is necessary to press, with a highpressure, the photosensitive cover lay film in order to bond thephotosensitive cover lay film with a CCL by pressing. Thus, the art isnot practical.

[0023] Further, in using the photosensitive resin composition or thephotosensitive cover lay film, how to expose them to the light anddevelop them is also an important factor. In general an alkali aqueoussolution is used in light-exposing and development. It is an advantagethat the photosensitive cover lay film whose main component is the(meth)acryl resin, can be surely developed because the (meth)acryl typeresin has a carboxyl group, which is a hydrophilic group. However, asdescribed above, the photosensitive cover lay film whose main componentis the (meth)acryl resin has a problem that the film, after curing,becomes poor in heat resistance, chemical resistance, and foldingresistance.

[0024] As described above, in case the photosensitive resin composition,or the photosensitive film produced therefrom is used in the electronicparts, it is not easy to attain sufficient properties both before andafter curing. Thus, there is a limit in raw materials to use for theproduction of the photosensitive resin composition and thephotosensitive film.

[0025] The present invention is contrived in view of the foregoingproblems. An object of the present invention is to provide (a) aphotosensitive resin composition that contains a polyimide, that hasexcellent properties, and that has a high practicability to be suitablyused in electronic parts and the like, (b) a photosensitive cover lay, afilm photosensitive film, and a laminate, which are produced from thephotosensitive resin composition, the film photosensitive film beingsuitable for use as a photosensitive dry resist film.

DISCLOSURE OF INVENTION

[0026] The inventors of the present invention, as a result of diligentstudy in view of the aforementioned problem, found out that use of acomposition in which at least a (A) soluble polyimide having aparticular structure and a (B) (meth)acrylic compound containing atleast one carbon-carbon double bond makes it possible to attain aphotosensitive film and a laminate having excellent properties, whichare suitably employable as a photosensitive cover lay film and aphotosensitive dry film resist. The present invention is based on thefinding.

[0027] Specifically, a photosensitive resin composition of the presentinvention contains a (A) soluble polyimide and a (B) (meth)acryliccompound, the (A) soluble polyimide (i) being soluble in an organicsolvent and (ii) having at least one of a structural unit represented byFormula (1):

[0028] and a structural unit represented by Formula (2):

[0029] (where, in each formula, R¹ is a tetravalent organic group, R² isa divalent organic group having a siloxane structure or an aromatic ringstructure, R³ is a divalent group having, in its structure, a hydroxylgroup, a carboxyl group, or a carbonyl group), and the (B) (meth)acryliccompound having at least one carbon-carbon double bond.

[0030] Furthermore, the photosensitive resin composition of the presentinvention preferably contains a (C) photo reaction initiator, and morepreferably contains a (D) fire retardant.

[0031] Moreover, a photosensitive film of the present invention isproduced by forming the photosensitive resin composition in a film-likeshape, and a laminate of the present invention includes a photosensitivelayer produced from the photosensitive resin composition.

[0032] In the above arrangements, the components (A) and (B) areessentially contained, and the component (C) is contained morepreferably. Thus, the arrangements attain a photosensitive resincomposition in which a sufficient mechanical strength is realized,together with excellent heat resistance, excellent processability, andexcellent adhesive property. A photosensitive film produced from thephotosensitive resin composition has excellent properties such as (1)being capable of being, directly and without using an adhesive agent,laminated on a target object to which the photosensitive film is to belaminated,

[0033] (2) having excellent heat resistance and flexibility after beingcured, (3) being able to be developed with an alkali aqueous solution,(4) having excellent heat resistance and chemical resistance aftercuring the film, and (5) the like properties.

[0034] Furthermore, by the arrangement in which the component (D) iscontained, it is possible to let the cured film to have an excellentflame resistance. Further, by using a non-halogen type compound as thecomponent (D), it is possible not only to satisfy the strict flameresistance standard but also to attain a non-pollution-causing property,low toxic property, highly safe property and the like properties.

[0035] The photosensitive resin composition having the abovearrangement, and the photosensitive film and laminate in which thephotosensitive resin composition is used, are applicable especially as aphotosensitive cover lay film and a photosensitive dry film resist, andcan be used, for example, (i) in a printed substrate, especially, aflexible printed wiring board, (ii) as a suspension in a head of a harddisc apparatus, and (iii) for the like.

[0036] For a fuller understanding of the nature and advantages of theinvention, reference should be made to the ensuing detailed descriptiontaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

[0037]FIG. 1 is a plan view illustrating an example of a circuit havingcomb-shaped pattern used in an FPC, when using a photosensitive film ofan embodiment of the present invention.

[0038]FIG. 2 is a plan view illustrating how to measure line-to-lineinsulating resistance of the circuit having a comb-shaped pattern foruse in an FPC, when using a photosensitive film of another embodiment ofthe present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0039] An embodiment of the present invention is described in detailbelow. Note that the present invention is not limited to this.

[0040] A photosensitive resin composition of the present inventioncontains at least a (A) soluble polyimide that is soluble in an organicsolvent, the (A) soluble polyimide synthesized from an acid dianhydridecomponent and at least one of (i) a diamine component containing asiloxane structure and an aromatic ring structure, and (ii) a diaminecomponent having, in its structure, a hydroxyl group, a carboxyl group,or a carbonyl group, and a (B) (meth)acrylic compound having at leastone carbon-carbon double bond.

[0041] Moreover, a photosensitive film of the present invention isproduced from the photosensitive resin composition. A laminate of thepresent invention is so arranged as to include (a) a photosensitivelayer that is produced from the photosensitive resin composition, or (b)the photosensitive film as a photosensitive layer.

[0042] <(A) soluble polyimide>

[0043] To begin with, a (A) soluble polyimide denotes a polyimide thatis so soluble to a below-exemplified organic solvent that, at atemperature in a range of 20° C. to 50° C., 100 g of the organic solventdissolves therein 11.0 g or more, preferably 5.0 g or more, morepreferable 10 g or more of the soluble polyimide. If the solublepolyimide is less soluble, there is a possibility that it becomesdifficult to produce the photosensitive film with a desired thickness.

[0044] Examples of the organic solvent for dissolving the (A) solublepolyimide are: (a) formamide-based solvents such asN,N-dimethylformamide, N,N-diethylformamide, and the like, (b)acetoamide-based solvents such as N,N-dimethylacetamide,N,N-diethylacetamide, and the like, (c) pyrrolidone-based solvents suchas N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, and the like;phenol-based solvents such as phenol, o-, m-, or p-cresol, xylenol,phenol halides, catechol, and the like; ether-based solvents such astetrahydrofuran, dioxane, dioxolane, and the like; alcohol-basedsolvents such as methanol, ethanol, butanol, and the like;cellosolve-based solvents such as butyl cellosolve and the like;hexamethylphosphoramide; and y-butyrolactone.

[0045] Especially, in the present invention, it is preferable to usetetrahydrofuran as the solvent for dissolving the (A) soluble polyimidetherein. That is, the (A) soluble polyimide of the present invention ispreferably a soluble polyimide that is so soluble to tetrahydrofuranthat, at a temperature at 20° C., 100 g of tetrahydrofuran dissolvestherein 1.0 g or more, preferably 5.0 g or more, more preferable 10 g ormore of the soluble polyimide.

[0046] A (A) soluble polyimide used in the present invention is asoluble polyimide (i) being soluble in an organic solvent and (ii)having at least one of a structural unit represented by Formula (1):

[0047] and a structural unit represented by Formula (2):

[0048] Note that each R¹ in Formulas (1) and (2) is independently atetravalent organic group. R² is a divalent organic group containing asiloxane structure or an aromatic ring structure, R³ is a divalent groupcontaining a hydroxyl group, a carboxyl group, or a carbonyl group inits structure.

[0049] The photosensitive resin composition of the present invention canrealize excellent properties, provided that the (A) soluble polyimidethus arranged is used in the photosensitive resin composition.

[0050] <(A-1) soluble polyimide>

[0051] A specific example of the (A) soluble polyimide containing thestructural unit of Formula (1) may be a polyimide containing astructural unit represented by Formula (3):

[0052] For easy explanation, this polyimide is referred to as (A-1)soluble polyimide.

[0053] In Formula (3), R¹¹″ is a tetravalent group containing anaromatic ring structure or an alicyclic structure, R²¹ is at least oneof (i) a siloxane structure that contains a siloxane bonding (—Si—O—),and (ii) an aromatic ring structure that contains a benzene ring. As aspecific example, a siloxane structure may be very preferablyrepresented by Formula (4):

[0054] Note that, in Formula (4), each R²² is independently a divalenthydrocarbon group or a divalent phenyl group, each R²³ is independentlyan alkyl group having one to three carbon atoms, or a phenyl group, anda is an integer of 3 to 30.

[0055] Moreover, as a specific example of the aromatic ring structure asR²¹, a structure represented in Formula (5) may be given verypreferably:

[0056] Note that, in Formula (5), each R²⁴ is independently a hydroxylgroup or a carboxyl group, R²⁵ is a direct bond or a divalent organicgroup selected from Group (6):

[0057] where b is an integer of 0 to 3, c is an integer of 1 or 2.Further, each R²⁶ in group (6) is independently a hydrogen atom, amethyl group, or a methyl halide group. In the methyl halide, a numberof hydrogen substituted with a halide/s may be in a range of 1 to 3.

[0058] As described above, with the arrangement in which the solublepolyimide is the polyimide containing at least one of the structurerepresented by Formula (4) and the structure represented by Formula (5),it is possible to give high heat resistance and high chemical resistanceto the photosensitive resin composition and photosensitive film obtainedfrom the polyimide.

[0059] Specifically, the polyimide (A-1) may be a first polyimide(A-1-1) or a second polyimide (A-1-2), the first polyimide (A-1-1)having a recurring unit presented by Formula (7):

[0060] (where R¹¹ is identical with R¹¹ in Formula (3), R²² and R²³ areidentical with R²² and R²³ in Formula (4), and a is any one of integers3 to 30), and the second polyimide (A-1-2) having a recurring unitrepresented by Formula (8):

[0061] (where R¹¹ is identical with R¹¹ in Formula (3), R²⁴ and R²⁵ arerespetively identical with R²⁴ and R²⁵ in Formula (5), b is any one ofintegers 0 to 3, and c is an integer of 1 or 2).

[0062] In other words, the polyimide (A-1-1) is the (A-1) solublepolyimide in which R²¹ in Formula (3) is the siloxane structurerepresented by Formula (4), and the polyimide(A-1-2) is the (A-1)soluble polyimide in which R²¹ in Formula (3) is the aromatic ringstructure represented by Formula (5).

[0063] The photosensitive resin composition of the present invention isso arranged that as to contain at least one of the firstpolyimide(A-1-1) and the second polyimide(A-1-2), as the (A-1) solublepolyimide. However, it is more preferable that the photosensitive resincomposition have both the two types of the polyimides. It is morepreferable that, besides the two types of the polyimides, thephotosensitive resin composition further contain a polyimide other thanthe two types of the polyimides. Specifically, the other polyimide is apolyimide in which R²¹ is a structure (divalent organic group) otherthan the siloxane structure represented by Formula (4), and the aromaticring structure represented by Formula (5). For easy explanation, theother polyimide is denoted as a “third polyimide”. Therefore, thephotosensitive resin composition of the present invention may contain apolyimide (the third polyimide) that is other than the (A) solublepolyimide. Note that it is possible to describe the third polyimide as apolyimide that has a recurring unit having a structure represented byFormula (3) in which R²⁰ is replaced with R²¹.

[0064] Here, there is no particular limit in how much the solublepolyimides (A-1) of two types are contained. However, it is preferablethat first polyimide(A-1-1) content and second polyimide(A-1-2) contentare respectively in a range of 5 mol % to 80 mol %, and in a range of0.5 mol % to 80 mol %, where the total amount of the firstpolyimide(A-1-1) and the second polyimide(A-1-2) (the total amount ofthe (A-1) soluble polyimide) is 100 mol %. Moreover, third polyimidecontent is the rest. With this arrangement, it is possible to attainmore improved property of the resultant photosensitive resin compositionand photosensitive film.

[0065] <(A-2) Soluble Polyimide>

[0066] Specifically, the (A) soluble polyimide having a structural unitof Formula (2) may be a polyimide having a recurring unit represented byFormula (9):

[0067] Note that the polyimide is referred to as a “(A-2) solublepolyimide”, for easy explanation.

[0068] In Formula (9), R¹¹ is identical with R¹¹ in Formula (3), R³⁰ isa divalent organic group, R³¹ is trivalent organic group, R³² is ahydroxyl group, a carboxyl group, or a monovalent organic group selectedfrom Group (10) listed below, d is an integer not less than 0, and e isan integer not less than 1:

[0069] Further, R³³ in Group (10) is a monovalent organic group havingat least one functional group selected from the group consisting of anepoxy group, a carbon-carbon triple bond, and a carbon-carbon doublebond.

[0070] The (A-2) soluble polyimide is arranged such that R³¹ in Formula(9) has a structure that is R³ in Formula (2) described above, that is,a divalent organic group having a hydroxyl group, a carboxyl group or acarbonyl group. More preferably, R³¹ in Formula (9) is an aromatic ringstructure in Formula (11) or (12). Moreover, R³⁰ in Formula (9) may be asiloxane structure of Formula (13), besides the aromatic ring structureof Formula (11) or

[0071] (12):

[0072] R³⁴ in Formula (11) is a direct bond, —CH₂—, —C(CH₃)₂—,—C(CF₃)₂—, —O—, —CO—, —COO—, or —SO₂—. Each R³⁵ in Formula (11) isindependently a hydroxyl group or a carboxyl group. Each R³⁶ in Formula(11) is independently a hydrogen atom, a hydroxyl group, a carboxylgroup, a halogen atom, a methoxy group, or an alkyl group having one tofive carbon atoms. In Formula (11), f is an integer of 0 to 4, each gand each h is independently an integer of 0 to 4.

[0073] Similarly, R³⁵ and R³⁶ in Formula (12) are respectively identicalwith R³⁵ and R³⁶ in Formula (11). R³⁷ in Formula (12) is a direct bond,—CO—, —O—, —C(CF₃)₂—, —C(CH₃)₂—, —COO—, or —SO2—. In Formula (12), f, g,and h are respectively identical with f, g and h in Formula (11).

[0074] Similarly, in Formula (13), each R³⁸ is independently an alkylgroup having one to twelve carbon atoms, a phenyl group, or a methoxygroup, i is an integer of 1 to 5, and j is an of 1 to 20.

[0075] As descried above, by the arrangement in which the (A) solublepolyimide is the polyimide that have at least any one of the structuresrepresented by Formulae (11),

[0076] (12), and (13), it is possible to give high heat resistance andhigh chemical resistance to the resultant photosensitive resincomposition and photosensitive film.

[0077] Moreover, solubility to an alkali aqueous solution is improvedbecause the (A-2) soluble polyimide has a hydroxyl group or a carboxylgroup in its side chain. Thus, it is possible to perform alkalidevelopment of the photosensitive resin composition or thephotosensitive film of the present invention.

[0078] Moreover, by the arrangement in which the (A-2) soluble polyimideis a modified polyimide having a monovalent organic group selected fromGroup (10), it is possible to give a high heat resistance, excellentmechanical properties, and excellent electric properties, to thephotosensitive resin composition that has been cured, or the curedphotosensitive film that has been cured.

[0079] <Structure of R¹>

[0080] Here, the (A-1) soluble polyimide and the (A-2) soluble polyimideare the (A) soluble polyimide in which R¹ in Formula (1) and R² inFormula (2) are specified. R₁ and R² are structures derived from adiamine component that is one of two monomers components that are usedas raw materials, as clearly understood from a later describedproduction method of the (A) soluble polyimide.

[0081] The (A) soluble polyimide of the present invention is arrangedsuch that the structure derived from the diamine component has eachstructure descried above. As to R¹ in Formulae (1) and (2)(corresponding to R¹¹ in Formula (3) or (9)), that is, a structurederived from an acid anhydride that is another monomer component used asa raw material, may be a tetravalent organic group regardless of whetherthe (A) soluble polyimide is the (A-1) soluble polyimide or the (A-2)soluble polyimide. However, it is preferable that, in Formula (3) or(9), R¹¹ is a tetravalent group selected from Group (14):

[0082] It is especially preferable that, in Formula (3) or (9), R¹¹ is atetravalent group selected from Group (15):

[0083] In Group (14), R¹² is a direct bond, —O—, —CH₂—, —CO—, —C(CH₃)₂—,—C(CF₃)₂—, —SO₂, —SO₂—, or a divalent organic group; each R¹³ isindependently —O—, or —COO—; R₁ ⁴ is a direct bond, —O—, —CH₂—, —CO—,—C(CH₃)₂—, —CH₂—C(CH₃)₂—CH₂—, a straight-chain alkyl group having 1 to20 carbon atoms, —C(CF₃)₂—, —SO₂, —SO₂, or a divalent organic group;each R¹⁵ is independently —COO— or —O—; R¹⁶ is —CH₂CH₂— or—C₆H₄—C(CH₃)₂—C₆H₄— or a divalent organic group. Similarly, in Group(15), R¹⁷ is a direct bond —C(CF₃)₂—, —CO—, or —O—; R¹⁸ is —COO— or —O—;R¹⁹ is —CH₂CH₂— or —C₆H₄—C(CH₃)₂—C₆H₄—, or a divalent organic group.

[0084] Especially, it is preferable that the (A-1) soluble polyimidecontains a tetravalent organic group R¹¹ selected from Group (15), andthe tetravalent organic group shares, by molar ratio, 10 mol % or morein the total amount of R¹ contained in the (A) soluble polyimide. Withthis arrangement, it is possible to attain more improved properties inthe resultant photosensitive resin composition and photosensitive film.

[0085] <Other Characteristics of the (A) Soluble Polyimide>

[0086] There is no particular limit in weight-average molecular weightof the (A) soluble polyimide of the present invention. However, theweight-average molecular weight of the (A) soluble polyimide of thepresent invention should be in a range of 10,000 to 300,000, while theweight-average molecular weight of the (A) soluble polyimide of thepresent invention is preferably in a range of 10,000 to 150,000, andmore preferably in a range of 30,000 to 100,000.

[0087] Moreover, it is preferable that the (A) soluble polyimide has aboiling point of 120° C. and is soluble in an organic solvent.

[0088] Moreover, in the present invention, especially in the arrangementin which the first polyimide(A-1-1) and the second polyimide(A-1-2) areused as the (A) soluble polyimide, it is preferable that the (A) solublepolyimide has a log-mean viscosity (0.5 g/100 ml) of 0.16 or more. Withthis arrangement, it is possible to attain the photosensitive resincomposition and photosensitive film of more improved properties.

[0089] <Production Method of (A) Soluble Polyimide>

[0090] Described below is a production method of the (A) solublepolyimide discussed above.

[0091] In general, polyimides are prepared by dehydrating a polyamicacid for imidization, the polyamic acid having been prepared by reactinga diamine and a tetracarboxylic dianhydride (acid dianhydride) in anorganic solvent. Especially, a polyimide prepared from an aromatictetracarboxylic dianhydride and an aromatic diamine is preferablebecause this polyimide easily attain a high molecular weight. On theother hand, use of aliphatic tetracarboxylic dianhydrides, which have alow reactivity, often faces a difficulty to attain a polyimide having ahigh molecular weight. Moreover, aliphatic diamines, which are highlybasic, are precipitated as a salt out of a solution system insynthesizing the polyamic acid, which is a precursor of the polyimide.Thus, use of aliphatic diamines has a difficulty to attain a polyimidehaving a high molecular weight.

[0092] Thus, it is preferable also in the present invention that thepolyimide prepared from an aromatic tetracarboxylic dianhydride and anaromatic diamine. Note that the tetracarboxylic dianhydride is justreferred to as an acid dianhydride, without limiting the aciddianhydride to aromatic or aliphatic one.

[0093] <Polymerization of Polyamic Acid>

[0094] The (A) soluble polyimide can be prepared from a polyamic acidthat is a precursor thereof. The polyamic acid is prepared by reacting,in an organic solvent, a diamine with an acid dianhydride. Specifically,under an inert atmosphere of argon, nitrogen, or the like, the diamineis dissolved in an organic solvent, or diffused in an organic solvent toa slurry. Then, the acid dianhydride dissolved in an organic solvent,diffused in an organic solvent to a slurry, or being in a solid state isadded into the diamine in the solvent, or into the slurry of thediamine. It is preferable that the polyamic acid thus obtained is apolyamic acid solution in which the polyamic acid is dissolved in theorganic solvent.

[0095] In this case, obtained is a polyamic acid whose structure isconstituted of an acid dianhydride and a diamine, if the diamine and theacid anhydride are substantially equimolar. Moreover, in case where twotypes or more of acid dianhydrides and two types or more of diamines areused, it is possible to arbitrarily obtain a polyamic acid copolymer, bysubstantially equimolarly regulating a molar ratio between a totalamount of the diamines and a total amount of the acid dianhydrides.There is no particular limit in how to carry out the polymerization byusing the diamines and the acid dianhydrides, by using the diamine andthe acid dianhydrides, or by using the diamines and the aciddianhydride.

[0096] For example, the solution of a polyamic acid polymer may beprepared as follows: diamine-1 and diamine-2 are added in an organicpolar solvent in advance; then the acid dianhydride is added therein;and polymerization is carried out. Moreover, the solution of a polyamicacid polymer may be prepared as follows: diamine-1 is added in anorganic polar solvent in advance; the acid dianhydride is added therein,then a resultant solution is stirred for a while; then, diamine-2 isadded; and polymerization is carried out. Alternatively, the solution ofa polyamic acid polymer may be prepared as follows: an acid dianhydrideis added in advance; then, diamine-1 is added, and then a resultantsolution is stirred for a while; then, diamine-2 is added, and then aresultant solution is stirred for a while; then, diamine-3 is added;then polymerization is carried out.

[0097] There is no particular limit in a temperature at which thereaction of the diamine and the acid anhydride is carried out. However,it is preferable that the reaction of the diamine and the acid anhydrideis carried out at a temperature in a range of −20° C. to 90° C.Moreover, there is no particular limit in how long the reaction of thediamine and the acid anhydride is performed, provided that the reactionis performed in a period in a range of 30 minutes to 24 hoursapproximately.

[0098] An average molecular weight of the polyamic acid thus obtained ispreferably in a range of 5,000 to 1,000,000, and more preferably in arange of 5,000 to 300,000. An average molecular weight of the polyamicacid less than 5,000 causes a low molecular weight of the (A) solublepolyimide finally obtained. When the (A) soluble polyimide having such alow molecular weight is used as it is, it tends to result in that a filmafter curing is fragile. On the other hand, an average molecular weightof the polyamic acid more than 1,000,000 tends to cause a high viscosityof the polyamic acid solution thus obtained. The polyamic acid solutionthus obtained would become difficult to handle due to the highviscosity.

[0099] <Organic Polar Solvent>

[0100] There is no particular limitation in which type of the organicpolar solvent is used in a synthesis reaction of the polyamic acid(reaction of the diamine and the acid dianhydride). Examples of theorganic polar solvents are: sulfoxide-based solvents such as dimethylsulfoxide, diethyl sulfoxide, and the like; formamide-based solventssuch as N,N-dimethylformamide, N,N-diethylformamide, and the like;acetamide-based solvents such as N,N-dimethylacetamide,N,N-diethylacetamide, and the like; pyrrolidone-based solvents such asN-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, and the like;phenol-based solvents such as phenol, o-, m-, or p-cresol, xylenol,phenol halide, catechol, and the like; ether-based solvents such astetrahydrofuran, dioxsane, dioxolane, and the like; alcohol-basedsolvents such as methanol, ethanol, butanol, and the like;cellosolve-based solvents such as butyl cellosolve, and the like;hexamethylphosphoramide, y-butyrolactone, and the like.

[0101] Those organic polar solvents may be used solely or in appropriatecombination as a mixture. Further, besides those organic polar solvents,aromatic hydrocarbons such as xylene, toluene, and the like. That is,there is no particular limitation in type of solvent used for thesynthesis reaction of the polyamic acid, provided that the solventdissolves the polyamic acid.

[0102] In a preferable production method of the (A) soluble polyimide(the preferable production method is described later), removal of theorganic solvent and imidization are carried out at once by heating,under reduced pressure, the polyamic acid solution thus obtained bysynthesizing the polyamic acid. Therefore, in terms of production steps,it is more advantageous to select the organic solvent that can dissolvethe polyamic acid therein, and, if possible, that has a lower boilingpoint.

[0103] <Imidization of the Polyamic Acid>

[0104] The photosensitive resin composition and photosensitive film ofthe present invention is prepared from the (A) soluble polyimide thathas been imidized. Thus, in the present invention, it is necessary toimidize the polyamic acid. Conventionally, the imidization is carriedout after bonding the photosensitive resin composition andphotosensitive film onto an FPC or the like. Thus, conventionally, it isnecessary to expose the polyamic acid to a high temperature of 250° C.or more for a long time. The exposure sometime deteriorates (i) a copperfoil on a surface of the FPC and (ii) that part of the surface of theFPC which is made of a compound other than the polyimide. In the presentinvention, no such deterioration of the FPC or the like is caused,because the photosensitive resin composition or photosensitive film thathas been imidized is used in the present invention.

[0105] The imidization of polyamic acid produces water. The water thusproduced easily causes hydrolysis of the polyamic acid, therebyresulting in a low molecular weight. Thus, it is preferable to carry outthe imidization while removing the water thus produced.

[0106] There is no particular limitation in how to carry out theimidization while removing the water. For example, the following threemethods are adoptable.

[0107] (1) A method in which the water is removed by azeotrope with anazeotrope solvent such as toluene, xylene, or the like.

[0108] (2) A chemical imidization method in which (i) an aliphatic aciddianhydride such as acetic anhydride, or the like, and (ii) a tertiaryamine such as triethylamine, pyridine, picoline, isoquinoline, or thelike, are added.

[0109] (3) A method in which imidization is carried out by heatapplication under reduced pressure.

[0110] In the method (1) in which the water is removed by azeotrope, thewater produced from the imidization is purposefully removed out of asystem by heating the water and the azeotrope solvent above theirboiling points. This method is quite effective for a polyimide that isdissolved in a solvent during heating.

[0111] In the chemical imidization method (2), the imidization iscarried out while chemically removing the thus produced water by turningthe aliphatic dianhydride into a fatty acid. After the imidization, thepolyimide solution is introduced into a solvent that is a poor solventwith respect to a polyimide, thereby precipitating the polyimide so asto purify the polyimide by removing the aliphatic acid dianhydride andthe tertiary amine that remain in a system.

[0112] In the method (3) in which the heat is applied under reducedpressure, the water produced from the imidization is heated under thereduced pressure, so as to be removed out of a system purposefully.

[0113] Any of the methods (1) to (3) may be adopted. However, the method(3) is most preferable, because it is possible to avoid reduction in themolecular weight by purposefully removing the water and inhibiting thehydrolysis.

[0114] In the method (3), a large molecular weight of the polyimide canbe expected, even in a case where (i) a tetracarboxylic acid, (ii) anacid dianhydride whose one anhydride is opened by addition of hydrogen,or (iii) the like, is present in the acid dianhydride used as the rawmaterial. To be specific, in case where an acid dianhydride whose oneanhydride is opened by addition of hydrogen is present in the aciddianhydride, there is a possibility that the polymerization reaction ofthe polyamic acid is stopped thereby resulting in a polyamic acid of alow molecular weight. Even in this case, by applying the heatapplication under the reduced pressure during the imidization, theopened ring of the acid dianhydride may be closed again so as to turnthe acid dianhydride having the opened ring into an acid dianhydride.Therefore, there is a possibility that, during the imidization, the aciddianhydride reacts with an amine remained in the system. Thus, there isa possibility that the molecular weight of the polyimide may becomelarger than the molecular weight of polyamic acid before imidization.

[0115] The following specifically explains how the imidization iscarried out in the method (3). Without particular limitation, any methodin which heat is applied to dryness under reduced pressure. In case abatch-type method is adopted, a vacuum oven may be used. In case acontinuous-type method is adopted, for example, an extruder having adecompressor may be used, for example. An extruder having two or threescrews is preferable. An amount to produce decides which type of methodsis to be used.

[0116] Note that the “extruder having a decompressor” performs heatapplication and fusion extrusion of thermoplastic resin. The extrudermay be an apparatus constructed by combining a general fusion extruder,for example, having two or three screws, with a device for removing thesolvent under the reduced pressure. Such apparatus may be constructed byattaching a decompressor to a conventional fusion extruder, or suchapparatus in which a function of decompressing additionally may bemanufactured. By using the apparatus, the polyamic acid is imidizedwhile the extruder mixes and kneads the polyamic acid solution. Thereby,the solvent and the water produced during the imidization are removed,thus leaving the produced soluble polyimide in a last stage of theimidization.

[0117] There is no particular limitation in heating conditions as to howmuch temperature is applied during the imidization, provided that thetemperature applied is in a range of 80° C. to 400° C. While it isnecessary that a lower limit of the temperature be 80° C., the lowerlimit of the temperature is preferably 100° C. or higher, and morepreferably 120° C. or higher. As long as the lower limit is at thetemperature, efficient imidization can be attained while it is alsopossible to remove the water efficiently. On the other hand, an upperlimit of the temperature is set at a temperature equal to or higher thana temperature at which thermolysis of the polyimide to be used takesplace. In general, the imidization is almost completed in a range of250° C. to 350° C. Thus, the upper limit of the temperature is setwithin this range.

[0118] As to the pressure reached by the decompression, a lower pressureis more preferable. However, the pressure is not particularly limited,provided that the pressure allows efficient removal of water that isproduced during the imidization performed with the heating condition.Specifically, it is necessary that the pressure of the heat applicationunder the reduced pressure be in a range of 0.09 Mpa to 0.0001 Mpa. Itis preferable that the pressure of the heat application under thereduced pressure is in a range of 0.08 Mpa to 0.0001 Mpa. And it is morepreferable that the pressure of the heat application under the reducedpressure is in a range of 0.07 Mpa to 0.0001 Mpa.

[0119] <Introduction of Functional Group>

[0120] In order to give a better reactivity and curing property to the(A) soluble polyimide thus obtained in the manner described above, anarrangement in which a modified polyimide is used is preferable. Themodified polyimide is obtained by reacting (i) a soluble polyimide towhich a hydroxyl group and/or a carboxyl group is introduced, with (ii)a compound having an epoxy group that is reactive with the solublepolyimide. The modified polyimide is excellent in reactivity and curingproperty because later-described functional groups are introduced in themodified polyimide.

[0121] It is preferable that the compound having an epoxy group furtherhas two or more photo polymerization and/or thermal polymerizationfunctional groups selected from the group consisting of an epoxy group,a carbon-carbon triple bond, and a carbon-carbon double bond. Byintroducing such photo polymerization and/or thermal polymerizationfunctional groups, it is possible to give a good curing property andbonding property to the resultant photosensitive resin composition orphotosensitive film.

[0122] Specifically, the modified polyimide that can be used as the (A)soluble polyimide in the present invention, is obtained by reacting,with a compound having an epoxy group, the (A-2) soluble polyimidedissolved in an organic solvent, the (A-2) soluble polyimide having atleast one recurring unit represented by Formula (9). Here, it ispreferable that the compound having an epoxy group is (i) epoxy resinhaving two or more epoxy groups, and (ii) a compound that has an epoxygroup and further has two or more functional groups selected from thegroup consisting of a carbon-carbon triple bond and a carbon-carbondouble bond.

[0123] The epoxy resin having two or more epoxy groups is notparticularly limited, provided that the epoxy resin has two or moreepoxy groups in its molecule.

[0124] Specific examples are: bis phenol-based epoxy resin such asEpicoate 828 (product name, made by Yuka Shell Corp.) and the like,ortho cresol novolak-based epoxy resin such as 180S65 (product name,Yuka Shell Corp.); bis phenol A novolak-based epoxy resin such as 157S70(product name, Yuka Shell Corp.) and the like; trishydroxyphenylmehtanenovolak-based epoxy resin such as 1032H60 (product name, Yuka ShellCorp.); naphthalenealkyl novolak-based epoxy resin such as ESN 375(product name, made by Nippon Steel Chemical Co., Ltd.) and the like;glycidyl amine-based resin such as tetraphenyrolethane 1031S (productname, Yuka Shell Corp.), YGD 414S (product name Toto Chemicals Corp.),trishydroxyphenylmethane EPPN 502H (product name, Nippon Kayaku Co.,Ltd.), Special bisphenol VG 3101L (product name, made by MitsuiChemicals Inc.), special naphthol NC 7000 (product name, Nippon KayakuCo., Ltd.), TETRAD-X, TETRAD-C (product names, Mitsubishi Gas ChemicalCompany Inc.), and the like; and the like.

[0125] There is no particular limitation as to an amount of the epoxyresin to add. However, it is preferable that the amount of the epoxyresin is within a range of 1 to 30 parts by weight with respect to 100parts by weight of the (A-2) soluble polyimide. If the amount of theepoxy resin is less than 1 part by weight, it cannot be expected thatthe resultant photosensitive resin composition or photosensitive filmhave an improved bonding strength with respect to the copper foil. Onthe other hand, the amount of the epoxy resin exceeding 30 parts byweight is not preferable because the cured film tends to be hard andfragile if the amount of the epoxy resin is more than 30 parts byweight.

[0126] The compound having an epoxy group and a carbon-carbon doublebond is not particularly limited, provided that the compound has anepoxy group and a double bond in its molecule. Specifically, examples ofthe compound having an epoxy group and a carbon-carbon double bond are:acrylglycidyl ether, glycidyl acrylate, glycidyl methacrylate, glycidylvinyl ether, and the like.

[0127] Further, the compound having an epoxy group and a carbon-carbontriple bond is not particularly limited, provided that the compound hasan epoxy group and a triple bond in its molecule. Specifically, examplesof the compound having an epoxy group and a carbon-carbon triple bondare: propargyl glycidyl ether, glycidyl propionate ethynylglycidylether, and the like.

[0128] Moreover, the curing progresses efficiently by an arrangement inwhich an epoxy curing agent is added in an amount in a range of 1% to10% by weight with respect to an amount of the epoxy resin to be added.The epoxy curing agent is not particularly limited, and may be any wellknown epoxy curing agent such as: amine compounds such as4,4′-diaminodiphenylmethane and the like; imidazole compounds; aciddianhydrides; phenol resin; acidic curing agents; and the like.Moreover, various coupling agents may be mixed in.

[0129] There is no particular limitation in the organic solvent used fordissolving the (A-2) soluble polyimide therein so as to react the (A-2)soluble polyimide with the compound having the epoxy group, providedthat the organic solvent is inert with the epoxy group and dissolves the(A-2) soluble polyimide having the hydroxyl group and/or carboxyl group.Specifically, examples of the organic solvent are: ether-based solventssuch as tetrahydrofuran, dioxsane, and the like; alcohol-based solventssuch as methanol, ethanol, butanol and the like; cellosolve solventssuch as butyl cellosolve and the like; hexamethylphosphoramide,y-butyrolactone; aromatic hydrocarbons such as xylene, toluene, and thelike; and the like. Those organic solvents may be used solely or inappropriate combination thereof as a mixture. Because the organicsolvent is removed in a later stage, to select an organic solvent thathas a lower boiling point is more advantageous in terms of production.

[0130] A reaction temperature at which the (A-2) soluble polyimidedissolved in the organic solvent is reacted with the compound having theepoxy group, is preferably is carried out at a temperature in a range of40° C. to 130° C. In this range of temperature, the epoxy group reactswith the hydroxyl group/carboxyl group. Especially, for the compoundhaving the epoxy group and the double bond or the triple bond, it isdesirable that the reaction is carried out at a temperature at which thedouble bond or the triple bond is not cross-linked or polymerized byheat. Specifically, a temperature in a range of 40° C. to 100° C. ispreferable, whereas a temperature in a range of 50° C. to 80° C. is morepreferable. Moreover, reaction time is not particularly limited,provided that a lower limit of the reaction time is about one hour andan upper limit of the reaction time is about 15 hours.

[0131] A modified polyimide solution can be obtained in the mannerdescribed above. In case where a target object on which the modifiedpolyimide is to be layered is the copper foil, the modified polyimidesolution may be so arranged as to appropriately contain thermosettingresin or thermoplastic resin for giving the modified polyimide solutionbetter development property and better bonding property with respect tothe copper foil. Thermosetting resin may be epoxy resin, acryl resin,cyanate ester resin, bismaleimide resin, bis allyl nadiimide resin,phenol resin, and the like. Thermoplastic resin may be polyester,polyamide, polyurethane, polycarbonate, and the like.

[0132] <Acid Dianhydride>

[0133] The acid dianhydride used for obtaining the (A) soluble polyimide(and the polyamic acid that is the precursor thereof) of the presentinvention is not particularly limited. For giving the soluble polyimidesolution a better heat resistance, it is preferable to use an aciddianhydride having one to four aromatic rings, or a cycloaliphaticdianhydride. Especially, in order to give the (A) soluble polyimide ahigher solubility with respect to the organic solvent, it is preferableto arrange such that, in addition to the acid dianhydride, an aciddianhydride is used which has two or more aromatic rings and is selectedfrom compounds represented by structures in Group (101):

[0134] Further, it is more preferable to arrange such that in additionto the acid dianhydride, an acid dianhydride is used which has four ormore aromatic rings.

[0135] Alternatively, as to the acid dianhydride used for preparing the(A) soluble polyimide (and the polyamic acid) of the present invention,it is possible to use, in addition to the acid dianhydride, an aciddianhydride selected from compounds having the following structuresshown in Group (102):

[0136] Especially, in the (A-1) soluble polyimide represented by Formula(3), it is especially preferable that the pyromellitic dianhydride andthe acid dianhydride that is selected from Group (102) are used to shareat least 10 mol % or more in R¹¹.

[0137] Note that R¹², R¹³, R¹⁴, R¹⁵, and R¹⁶ in Groups (101) and (102)are identical with R¹², R¹³ μl⁴, R¹⁵, and R¹⁶ in Group (14).

[0138] Especially, in Group (102), it is preferable that the aciddianhydride is an acid dianhydride represented by Formula (103):

[0139] (where R¹⁷ is any one of a direct bond, —C(CF₃)₂—, —CO—, and —O—,R¹⁸ is —COO— or —O—, R¹⁹ is —CH₂CH₂—, —C₆H₄—C(CH₃)₂—C₆H₄—, or a divalentorganic group).

[0140] Especially, the divalent organic group of R¹⁹ may have thefollowing structures:

[0141] Note that each R¹⁰ in each structure is independently any one ofa hydrogen atom, a halogen atom, a methoxy group, and an alkyl grouphaving 1 to 16 carbon atoms.

[0142] Moreover, specifically, the acid dianhydride having one to fouraromatic rings or the cycloaliphatic acid dianhydride may be thefollowing compounds.

[0143] For example, aliphatic or cycloaliphatic tetracarboxylicdianhydrides such as 2,2′-hexafluoropropyridine diphthalic dianhydride,2,2-bis(4-hydroxyphenyl)propanedibenzoate-3,3′,4,4′-tetra carboxylicdianhydride, butanetetracarboxylic dianhydride,1,2,3,4-cyclobutanetetracarboxylic dianhydride,1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic acid,1,2,3,4-cyclopentanetetracarboxylic dianhydride,2,3,5-tricarboxycyclopenthylacetic dianhydride,3,5,6-tricarboxylnorbornane-2-acetic dianhydride,2,3,4,5-tetrahydrofuran tetracarboxylic dianhydride,5-(2,5-dioxotetrahydrofural-3-methyl-3-cyclohexene-1,2-di carboxylicdianhydride, bicyclo[2,2,2]-octo-7-en-2,3,5,6-tetracarboxylic aciddianhydride, and the like; pyromellitic dianhydride, 3, 3′,4,4′-benzophenonetetracarboxylic dianhydride,3,3′,4,4′-biphenylsulfoneteteracarboxylic dianhydride,1,4,5,8-naphthalenetetracarboxylic dianhydride,2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3′4,4′-biphenylethertetracarboxylic dianhydride,3,3′,4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride,3,3′,4,4′-tetraphenylsilanetetracarboxylic dianhydride,1,2,3,4-furantetracarboxylic dianhydride,4,4′-bis(3,4-dicarboxylphenoxy) diphenylsulfide dianhydride,4,4′-bis(3,4-dicarobxyphenoxy) diphenylsulfone dianhydride,4,4′bis(3,4-dicarboxyphenoxy) diphenylpropane dianhydride,3,3′,4,4′-perfluoroisopropyrridine diphthalic dianhydride,3,3′4,4′-biphenyltetracarboxylic dianhydride,bis(phthalic)phenylphosphinateoxide dianhydride,p-phenylene-bis(triphenylphthalic) dianhydride,m-phenylene-bis(triphenylphthalic) dianhydride,bis(triphenylphthalic)-4,4′-diphenyl ether dianhydride,bis(triphenylphthalic)-4,4′-diphenylmethane dianhydride, and the like,1,3,3a,4,5,9b-hexahydro-2,5-dioxo-3-franyl)-naphtho[1,2-c]fran-1,3-dione,1,3,3a,4,5,9b-hexahydro-5-methyl-5-(tetrahydro-2,5-dioxo-3-franyl)-naphtho[1,2-c]fran-1,3-dione,1,3,3a,4,5,9b-hexahydro-8-methyl-5-(tetrahydro-2,5-dioxo-3-franyl)-naphto[1,2-c]fran-1,3-dion, and the like. Those dianhydrides may beused solely, or in combination by using two or more of them.

[0144] Moreover, especially in case where the (A) soluble polyimidecontains the siloxane structure represented by Formula (4), that is, incase where the (A) soluble polyimide is “polyimide siloxane”, it ispossible to preferably use the following compounds as the aciddianhydride:

[0145] For example, 1,4,5,8-naphthalenetetracarboxylic dianhydride,2,3,6,7-naphthalenetetracarboxylic dianhydride,3,3′,4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride,3,3′4,4′-tetraphenylsilanetetracarboxylic dianhydride,1,2,3,4-frantetracarboxylic dianhydride,4,4′-bis(3,4-dicarboxyphenoxy)diphenylsulfide dianhydride,4,4′-bis(3,4-dicarboxyphenoxy)diphenylsulfone dianhydride4,4′-bis(3,4-dicarboxyphenoxy)diphenylpropane dianhydride,bis(phthalic)phenylphosphinateoxide dianhydride,p-phenylene-bis(triphenyl phthalic) dianhydride,m-phenylene-bis(triphenyl phthalic) dianhydride, bis(triphenylphthalic)-4,4′-diphenyl ether dianhydride, bis(triphenylphthalic)-4,4′-diphenylmethane dianhydride, and the like, aromatictetracarboxylic dianhydrides Those dianhydrides may be used solely or incombination by using two or more of them.

[0146] <Diamine>

[0147] The diamine that is used for preparing the (A) soluble polyimide(and the polyamic acid that is the precursor thereof) of the presentinvention is not particularly limited. However, it is preferable that atleast part of a total diamine component is a diamine having a hydroxylgroup and/or a carboxyl group in its molecule. With the arrangement, itis possible to cause the resultant (A) soluble polyimide to have ahydroxyl group and/or a carboxyl group. Therefore, it is possible toattain (i) the resultant photosensitive resin composition having abetter solubility with respect to alkali aqueous solutions, and (ii) theabove mentioned denature polyimide. Especially, the better solubilitywith respect to the alkali aqueous solutions allows to develop theresultant photosensitive resin composition or photosensitive film byusing an alkali aqueous solution.

[0148] For attaining a good balance between the heat resistance and thedevelopment property by using the alkali aqueous solution, it ispreferable that the diamine having a hydroxyl group and/or carboxylgroup is an aromatic diamine represented by the following Formula

[0149] Especially, it is possible to attain a polyimide having a bettersolubility with respect to the alkali aqueous solution, by the use ofdiamine in which R³⁶ in Formula (104) is a hydroxyl group or a carboxylgroup. Those diamine compounds may be used solely or in combination byusing two or more of them.

[0150] Note that in Equation (104), R³⁴, R³⁵, R³⁶, f, g, and h areidentical with R³⁴, R³⁵, R³⁶, f, g, and h in Formula

[0151] Moreover, the other aromatic diamine may be an aromatic diaminerepresented by Formula (105):

[0152] Note that in Formula (105), R³⁵, R³⁶, R³⁷, f, g, and h areidentical with R³⁵, R³⁶, R³⁷, f, g, and h in Formula (12).

[0153] Moreover, for both of the aromatic diamines represented byFormulas (104) and (105), an amount of the aromatic diamine to be usedis preferably in a range of 5 mol % to 95 mol %, and more preferably ina range of 10 mol % to 70 mol %, with respect to a total diaminecomponent, for attaining a higher solubility of the resultant (A)soluble polyimide with respect to the organic solvent.

[0154] Moreover, for attaining a higher solubility of the (A) solublepolyimide with respect to the organic solvent, it is preferable that thearomatic diamine represented by Formula (104) is used in a range of 5mol % to 95 mol % with respect to a total diamine component, and it ismore preferable that the aromatic diamine represented by Formula (104)is used in a range of 10 mol % to 70 mol %, with respect to a totaldiamine component.

[0155] Furthermore, for attaining better flexibility of the cured film,it is more preferable that, as the acid dianhydride used for preparingthe (A) soluble polyimide (and the polyamic acid that is the precursorthereof), (siliconediamine) is contained as a siloxanediaminerepresented by Formula (106):

[0156] Note that in Formula (106), R³⁸, i, and j are identical with R³⁸,i, and j in Formula (13).

[0157] It is preferable for attaining lower elasticity of the film thatthe siloxanediamine represented by Formula (106) is used in a range of 5mol % to 95 mol % with respect to the total diamine component. If theamount of the siloxanediamine is less than 5 mol %, it is not possibleto attain sufficient effect of the addition of the siloxanediamine. Ifthe amount is more than 50 mol %, the film tends to become too soft andthe elasticity thereof tends to become too low, and a thermal expansionefficient thereof tends to become a large.

[0158] Further, for obtaining especially the (A-1) soluble polyimide asto the (A) soluble polyimide, it is preferable to use an aromaticdiamine represented by the following Formula (107) and thesiloxanediamine represented by the following Formula (108):

[0159] Note that in Formula (107) R²⁴ and R²⁵, b, and c are identicalwith R²⁴ and R²⁵, b, and c in Formula (5). Similarly, in Formula (108),R²² and R²³, and a are identical with R²² and R²³, and a in Formula (4).

[0160] Moreover, in the siloxanediamine of Formula (108), a may be 3 to30. However, it is preferable that a is in a range of 5 to 20, and it ismore preferable that a is in a range of 6 to 16. if a is below therange, the improved flexibility and solubility that are typicallyattained by siloxane boding cannot be expected. Moreover, it is notpreferable that a is above the range, because a above the range tends tocause lower heat resistance. Further, in Formula (108), it is especiallypreferable that R²³ is a methyl group, and R²² is —(CH2)_(n)— (where nis an integer of 2 to 6).

[0161] Of the aromatic diamines, the most preferable is the aromaticdiamine represented by Group (109):

[0162] (where R²⁷ is —O—, —S—, —CO—, —CH₂—, —SO₂—, —C(CH₃)₂—, —C(CF₃)₂—,—O—CH₂—C(CH₃)₂—CH₂—O—, each z is independently an integer of 1 to 3, andm is an integer of 1 to 4). The aromatic diamine represented by Formula(109) is suitable because it is easy to obtain the aromatic diamineindustrially.

[0163] Specific examples of the aromatic diamine are: diaminophthalicacids such as 2,5-diaminoterephthalic acid and the like; carboxybiphenylcompounds such as 3,3-diamino-4,4-dicarboxybipheny4,4-diamino-3,3-dicarboxybipheny 4,4′-diamino-2,2′-dicarboxybiphenyl,4,4′-diamino-2,2′5,5′-tetracarboxybiphenyl, and the like,carboxydiphenyl alkanes such as carboxydipheny methanes and the likesuch as 3,3′-diamino-4,4′-dicarboxydiphenylmethane,2,2-bis[3-amino-4-carboxyphenyl]propane,2,2-bis[4-amono-3-carboxyphenyl]propane,2,2-bis[3-amino-4-carboxyphenyl]hexafuluoropropane,4,4′-diamino-2,2′,5,5′-tetracarboxydiphenylmethane, and the like;carboxydiphenyl ether compounds such as3,3′-diamino-4,4′-dicarboxydiphenylether,4,4′-diamino-3,3′-dicarboxydiphe nylethe r,4,4′diamino-2,2′-dicarboxydiphenyl ether,4,4′-diamino-2,2′,5,5′-tetracarboxydiphenyether, and the like;diphenylsufone compounds such as3,3′-diamino-4,4′-dicarboxydiphenylsulfone,4,4′-diamino-3,3′-dicarboxydiphenylsulfone,4,4′diamino-2,2′-dicarboxydiphenylfulfone,4,4′diamino-2,2′5,5′-teteracarboxydiphenylsulfone, and the like;bis[(carboxypheny)phenyl]alkane compounds such as2,2-bis[4-(4-amino-3-carboxyphenoxy) phenyl] propane, and the like;bis[(carboxyphenoxy)phenyl]sulfone compounds2,2-bis[4-(4-amino-3-carboxyphenoxy)phenyl] sulfone and the like;diamino phenols such as 2,4-diaminophenol and the like; hydroxybiphenylcompounds such as 3,3′-diamino-4,4′-dihydroxybiphenyl,4,4′-diamino-3,3′-dihydroxybiphenyl, 4,4′-diamino-2,2′-dihydroxybipheny,4,4′-diamino-2,2′5,5′-tetrahydroxybiphenyl, and the likehydroxydiphenyalkanes such as hydroxydiphenylmethanes such as3,3′-diamino-4,4′-dihydroxydiphenylmethane,4,4′-diamino-3,3′-dihydroxydiphenylmethane,4,4′-diamino-2,2′-dihydroxydiphenylmethane, 2,2-bis[3-amino-4-hydroxyphenyl] propane,2,2-bis[4-amino-3-hydroxyphenyl]propane,2,2-bis[3-amino-4-hydroxyphenyl]hexafluoropropane,4,4′-diamino-2,2′5,5′-tetrahydroxydiphenylmethane and the like;hydroxydiphenylether compounds such as3,3′-diamino-4,4′-dihydroxydiphenyl ether,4,4′-diamino-3,3′-dihydroxydiphenylether,4,4′-diamino-2,2′-dihydroxydiphenylether,4,4′-diamino-2,2′5,5′-tetrahydroxydiphenylether, and the like;diphenylsulfone compounds such as3,3′-diamino-4,4′-dihydroxydiphenylsulfone,4,4′-diamino-3,3′-dihydroxydiphenylsulfone,4,4′-diamino-2,2-dihydroxydiphenysulfone,4,4′-diamino-2,2′,5,5′-tetrahydroxyphenylsulfone, and the like;bis[(hydroxyphenyl)phenyl]alkane compounds such as2,2-bis[4-(4-amino-3-hydroxyphenoxypheny)propane, and the like;bis(hydroxyphenoxyl)phenyl compounds such as4,4-bis(4-amino-3-hydroxyphenoxy)biphenyl and the like;bis[(hydroxyphenoxyl)phenyl]sulfone compounds such as2,2-bis[4-(4-amino-3-hydroxyphenoxy)phenyl]sulfone, and the like;diaminobenzoic acids such as 3,5-diaminobenzoic acid and the like;bis(hydroxyphenoxy)biphenyl compounds such as4,4′-diamino-3,3′-dihydroxydiphenylmethane,4,4′-diamino-2,2′-dihydroxydiphenylmethane, 2,2,-bis[3-amino-4-carboxyphenyl] propane,4,4′-bis(4-amino-3-hydroxyphenoxy)biphenyl, and the like. Those diaminesmay be used solely or in combination by using two or more of them.

[0164] Moreover, in case the aromatic diamine is used, the arrangementin which the aromatic diamine is a diamine having an amino group at m-position (3-) tends to attain a small light absorbance of the resultant(A) soluble polyimide in a wavelength band of g ray and i ray. Becauseof this, this arrangement is so advantageous for designingphotosensitive resin.

[0165] Other diamines that can be used in synthesis of the (A) solublepolyimide of the present invention is not particularly limited. Specificexamples of the other diamines are aromatic diamines such asp-phenylenediamine, m-phenylenediamine, 4,4′-diaminodiphenylmethane,4,4′-diaminophenylethane, 4,4′-diaminophenylether,4,4′-didiaminophenylsulfide, 4,4′didiaminophenysulfone,1,5-diaminonaphthalene, 3,3-dimethyl-4,4′-diaminobiphenyl,5-amino-1-(4′-aminophenyl)-1,3,3-trimethylindan,6-amino-1-(4′-aminophenyl)-1,3,3-trimethylindan,4,4′-diaminobenzanilide, 3,5-diamino-3′-trifluoromethylbezanilide,3,5-diamino-4′-trifluoromethylbezanilide, 3,4′-diaminodiphenyl ether,2,7-diaminofluorene, 2,2-bis(4-aminophenyl)hexafluoropropane,4,4-methlene-bis(2-chloroaniray),2,2′5,5′-tetrachloro-4,4′-diaminobiphenyl,2,2′-dichloro-4,4′-diamino-5,5′-dimethoxybiphenyl,3,3′dimethoxy-4,4′-diaminobiphenyl,4,4′-diamino-2,2′-bis(trifluromethyl)biphenyl,2,2-bis[4-(4-aminophenoxy)phenyl]propane,2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane,1,4-bis(4-aminophenoxy) benzene, 4,4′-bis(4-aminophenoxy)-biphenyl,1,3′-bis(4-aminophenoxy) benzene, 9,9-bis(4-aminophenyl) fluorene,4,4′-(p-phenyleneisopropylidene)bisaniray,4,4′-(m-phenyleneisopropylidene)bisaniray,2,2′-bis[4-(4-amino-2′-trifluoromethylphenoxy) phenyl]hexafluoropropane,4,4′-bis [4-(4-amino-2-trifluoromethyl)phenoxy]-octafluorobiphenyl, andthe like; aromatic diamines having two amino groups bonded with anaromatic ring such as diaminotetraphenylthiophene and the like, andhaving a hetero atom other than a nitrogen atom of the amino group;1,1-meta-xylenediamine, 1,3-propanediamine, tetramethylenediamine,pentamethylenediamine, octamethylenediamine, nonamethylenediamine,4,4-diaminoheptamethylenediamine, 1,4-diaminocyclohexane,isophoronediamine, tetrahydrodicyclopentadienylenediamine,hexahydro-4,7-methanoindanilenedimethylenediamine,tricyclo[6,2,1,02.7]-undesilenedimethyldiamine,4,4′-methylenebis(cyclohexylamine) and the like; aliphatic diamine andcycloaliphatic diamine; and the like. Those diamine may be used solelyor in combination by using two or more of them.

[0166] Here, the (A-1) soluble polyimide is polyimide siloxane having acarboxyl group (COOH) and a hydroxyl group (OH). The polyimide siloxanehas a COOH equivalent in a range of 250 to 3000, preferably in a rangeof 300 to 2000, and most preferably in a range of 300 to 1500. Note thatthe COOH equivalent denotes an average molecular amount per COOH.

[0167] A COOH equivalent above the range will cause the (A-1) solublepolyimide to be insoluble in the alkali aqueous solution that is used asthe developer, thereby prohibiting the development. Thus, the COOHequivalent above the range is not preferable. Moreover, a COOHequivalent below the range will cause the (A-1) soluble polyimide tohave a lower heat resistance. In addition, a large number ofwater-absorbing COOH in the (A-1) soluble polyimide causes the (A-1)soluble polyimide to be hygroscopic. Thus, the COOH equivalent below therange is not preferable.

[0168] Similarly, an OH equivalent in the polyimide siloxane ((A-1)soluble polyimide) is in a range of 250 to 3000, preferably in a rangeof 300 to 2000, most preferably in a range of 300 to 1500. Note that theOH equivalent is an average molecular weight per OH.

[0169] An OH equivalent above the range will causes the (A-1) solublepolyimide to be insoluble in an alkali solution that is used as thedeveloper, thereby inhibiting the development. Thus, the OH equivalentabove the range is not preferable. Moreover, an OH equivalent below therange will cause the (A-1) soluble polyimide to have a lower heatresistance. In addition, a large number of water-absorbing OH in the(A-1) soluble polyimide causes the (A-1) soluble polyimide to behygroscopic. Thus, the OH equivalent below the range is not preferable.

[0170] In order to attain the COOH equivalent and the OH equivalent, itis desirable to use a diamine which has two or more COOH or OH in itsmolecule. The use of this diamine enables copolymerization of anotherkind of diamine in realizing a predetermined carboxylic acid equivalent,thereby making it easier to design property. <Soluble Polyimide Content(Amount of Soluble Polyimide in Composition)>

[0171] (A) soluble polyimide content (the content includes the modifiedpolyimide) in the photosensitive resin composition of the presentinvention is preferably in a range of 30% to 70% by weight, morepreferably in a range of 40% to 60% by weight, and further preferably ina range of 45% to 60% by weight, based on a total amount (100% byweight) of the (A) soluble polyimide, the (B) (meth)acrylic compound,the (C) photo reaction initiator, and the (D) fire retardant. If the (A)soluble polyimide content is less than 30% by weight, it will becomedifficult to give the cured film fire retarding property. Further, itwill result in a poor mechanical property of the cured film. On theother hand, the (A) soluble polyimide content more than 70% by weighttends to cause the photosensitive film to have a poor developmentproperty.

[0172] <(B) (Meth)Acrylic Compound>

[0173] Next, it is so arranged that (B) (meth)acrylic compound of thepresent invention is a multifunctional (meth)acrylic compound having atleast one carbon-carbon double bond. By the arrangement in which thephotosensitive resin composition and photosensitive film contains suchcompound, it is possible to attain excellent photosensitivity of thephotosensitive resin composition and photosensitive film, therebyimproving usefulness of the photosensitive resin composition andphotosensitive film.

[0174] The (B) (meth)acrylic compound is not limited to specificexamples. However, especially, the (B) (meth)acrylic compound is soarranged as to be at least one of (1) a later-describedimide(meth)acrylate compound, and (2) (meth)acrylic compound having astructure having no imide ring (hereinafter, referred to as non-imide(meth)acrylic compound for easy explanation). It is preferable that bothof them are used.

[0175] <(1) Imide(Meth)Acrylate Compound>

[0176] The arrangement in which the photosensitive resin composition andphotosensitive film contain (1) the imide(meth)acrylate compound givesfire retarding property, soldering heat resistance, and foldingresistance to the cured photosensitive film.

[0177] Provided that (1) the imide(meth)acrylate compound is a(meth)acrylate compound having an imide ring, that (1) theimide(meth)acrylate compound is not particularly limited. However, it ispreferable that that (1) the imide(meth)acrylate compound is animide(meth)acrylate compound having a structure represented by Formula(16) or a structure represented by Formula (18):

[0178] The use of imide(meth)acrylate having the structures improvespost-curing chemical resistance and heat resistance.

[0179] Note that, in Formula (16), each R⁴¹ is independently a hydrogenatom or a methyl group, and R⁴² is a divalent organic group selectedfrom the following Group (17) and k is an integer of not less than 0:

[0180] (where R⁴³ is a monovalent organic group, m is an integer of 1 to4).

[0181] Moreover, in Formula (18), each R⁴⁴ is independently a hydrogenatom or a methyl group, R⁴⁵ is a tetravalent group selected from thefollowing Group (19), and n is an integer of not less than 0:

[0182] (where each R⁴⁶ and each R⁴⁷ is independently a divalent organicgroup, p is an integer of 0 to 5).

[0183] Further, in Group (17), the organic group R⁴³ is not particularlylimited provided that the organic group R⁴³ is a monovalent group.Preferably, the organic group R⁴³ may be a hydrogen atom; alkyl groupssuch as a methyl group, an ethyl group, a propyl group, a butyl group, apentyl group, and the like; alkyl ether groups such as a methoxy group,an ethoxy group, and the like; allyl groups; allyl ether groups;hydroxyl groups, carboxyl groups; halogen atoms; and the like. Aboveall, the organic group R⁴³ may be preferably a hydrogen atom, a methylgroup, a methoxy group, a hydroxyl group, a carboxyl group, and ahalogen atom.

[0184] Moreover, in Group (19), the organic group R⁴⁶ is notparticularly limited provided that the organic group R⁴⁶ is a divalentorganic group. Preferably, the organic group R⁴⁶ may be a directbonding, —CH₂—, —C(CH₃)₂—, —C(CF₃)₂—, —O—, —CO—, —SO₂—,—(CO)O-C_(m)H_(2m)-O(CO)-(m is an integer not less than 1), and thelike. Further, the organic group R⁴⁷ is not particularly limited,provided that the organic group R⁴⁷ is a divalent organic group.Preferably, organic group R⁴⁷ may be —O—, —COO—, and the like.

[0185] The (B) component used in the present invention: theimide(meth)acrylate compound can be synthesized by reacting an imidealcohol with an acrylic acid or a methacrylic acid, the imide alcoholbeing represented by Formula (110) or (111):

[0186] (where R⁴¹ is hydrogen or a methyl group, R⁴² is a divalentorganic group represented by Group (17), k is an integer of not lessthan 0),

[0187] (where R⁴⁴ is hydrogen or a methyl group, R⁴⁵ is a tetravalentorganic group represented by Group (19), and b is an integer of not lessthan 0).

[0188] The reaction is an esterification reaction. The reaction isstarted off from a mixture of (i) the imide alcohol represented by atleast one of Formulas (110) and

[0189] (111), and (ii) the acrylic acid or the methacrylic acid in aratio of 1:2 to 1:10, preferably in a ratio of 1:3 to 1:6, especiallypreferably in a ratio of 1:4 to 1:5.

[0190] In case where an organic solvent is used in the reaction, it ispreferably to use an organic solvent that can dissolve both of (i) atleast one of the imide alcohol represented by Formula (110) and theimide alcohol represented by Formula (111) which are a startingmaterial, and (ii) imide(meth)acrylate represented by Formulae (16) and(18), which are a reaction product. Generally, a polar organic solventis preferable. The polar organic solvent may be sulfolane,N,N′-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone,N,N′-dimethylpropyrene urine, and the like, for example. Above all, itis preferable to use sulfolane for better solubility and reactivity.

[0191] Moreover, it may be so arranged as to use an organic solventhaving a boiling point in a range of 30° C. to 150° C., in combinationwith the polar organic solvent. Such organic solvent is preferablebecause it is easy to prepare an azeotropic mixture of such organicsolvent and water. Such organic solvent may be benzene, toluene, xylene,ethylbenzene, hexane, cyclohexane, isopropylethers, diethylethers,methylethylketones, diethylketones, methylisobutylketones, carbontetrachloride, trichloroethylene, and the like, for example.

[0192] It is so arranged that (i) imide alcohol represented by Formulae(110) and (111) reacts with (ii) acrylic acid or methacrylic acid at atemperature in a range of 50° C. to 200° C., preferably in a range of100° C. to 180° C., and more preferably in a range of 120° C. to 150° C.Moreover, the reaction is performed in a duration in a range of 3 to 20hours, preferably in a range of 4 to 10 hours, and more preferably in arange of 5 to 6 hours.

[0193] It is possible to accelerate the reaction of (i) the imidealcohol and (ii) the acrylic acid or the methacrylic acid by using acatalyst. The catalyst may be well known esterification catalysts suchas: sulfuric acid; p-toluene sulfonic acid; benzenesulfonic acid;methane sulfonic acid; trifluoromethanesulfonic acid; zinc chloride;phosphoric acid; antimony oxide; ester titanate, methoxy phenol, and thelike. An amount of the catalyst to be used is in a range of 0.01% to 30%by weight, preferably in a ragne of 0.02% to 20% by weight, morepreferably in a ragne of 0.1% to 10% by weight, based on 100% by weightof imide alcohol.

[0194] After the reaction, a poor solvent with respect to the reactionproducts is added to a reaction solution. Precipitate thus produced isfiltered off, washed, and dried thereby obtaining imide (meth)acrylatein a powder form. The imide (meth)acrylate is reactive creature. Thepoor solvent may be, for example, tetrahydrofuran, acetone, methanol,ethanol, isopropyl alcohol, butanol, and the like.

[0195] Moreover, the imide alcohol, which is the starting material, canbe obtained by reacting a corresponding dicarboxylic anhydride ortetracarboxylic anhydride with a monoethanolamine in an organic solvent.Here, it is only required that a molar ratio between the dicarboxylicacid anhydride and the monoethanolamine be in a range of 1:1 to 1:5. Itis preferable that the molar ratio between the dicarboxylic acidanhydride and the monoethanolamine is in a range of 1:1 to 1:2.5. It ismore preferable that the molar ratio between the dicarboxylic acidanhydride and the monoethanolamine is in a range of 1:1 to 1:1.5. It isonly required that a molar ratio between the tetracarboxylic anhydrideand the monoethanolamine be in a ragne of 1:2 to 1:10. It is preferablethat the molar ratio between the tetracarboxylic anhydride and themonoethanolamine is in a range of 1:2 to 1:5. It is more preferable thatthe molar ratio between the tetracarboxylic anhydride and themonoethanolamine is in a ragne of 1:2 to 1:3.

[0196] As the organic solvent for use in synthesizing the imide alcohol,preferable is a polar organic solvent that can dissolve both of (i) thedicarboxylic anhydride or tetracarboxylic anhydride, and (ii) themonoethanolamine. Specifically, the organic solvent may be, for example,sulfolane, N,N′-dimethylacetamide, N,N′-dimethylformamide,N-methyl-2-pyrrolidone, N,N′-dimethylpropylene urine, and the like.Above all, it is preferable to use sulfolane for better solubility andreactivity.

[0197] Moreover, it may be so arranged as to use an organic solventhaving a boiling point in a range of 30° C. to 150° C. in combinationwith the polar organic solvent. It is easy to prepare an azeotropicmixture of such organic solvent and water. Such organic solvent may be,for example, benzene, toluene, xylene, ethylbenzene, hexane,cyclohexane, isopropylethers, diethylethers, methylethylketones,diethylketones, methylisobutylketones, carbon tetrachloride,trichloroethylene, and the like.

[0198] The reaction of (i) the dicarboxylic anhydride or tetracarboxylicanhydride with (ii) the monoethanolamine is carried out in a range of50° C. to 200° C., preferably in a range of 100° C. to 180° C., morepreferably in a range of 140° C. to 160° C. Moreover, the reaction iscarried out in a duration in a range of 3 to 20 hours, preferably in arange of 4 to 10 hours, and more preferably in a range of 5 to 7 hours.

[0199] By using a catalyst, it is possible to accelerate the reaction of(i) the dicarboxylic anhydride or tetracarboxylic anhydride with themonoethanolamine. The catalyst may be well-known esterificationcatalysts such as sulfuric acid, p-toluenesulfonic acid, zinc chloride,phosphoric acid, antimony oxide, ester titanate, methoxyl phenol, andthe like. An amount of the catalyst to be used is in a range of 0.01% to30% by weight, preferably in a range of 0.05% to 20% by weight, morepreferably in a ragne of 0.1% to 10% by weight, based on 100% by weightof the dicarboxylic anhydride or the tetracarboxylic anhydride.

[0200] The imide(meth)acrylate compound thus obtained may be used solelyor in combination by using two or more of them.

[0201] Moreover, the present invention may be so arranged as to use acommercially available imide(meth)acrylate compound. Specifically, forexample, the commercially available imide(meth)acrylate compound may be,but not limited to, allonix TO-1429 (product name: supplied by To agosei Co., Ltd).

[0202] <(2) Non-imide (Meth)Acrylic Compound>

[0203] The arrangement in which the (2) non-imide (meth)acrylic compoundis used in the photosensitive resin composition and photosensitive filmcauses the resultant photosensitive resin composition and photosensitivefilm to be flowable in thermo-compression bonding and further to have ahigh resolution.

[0204] The (2) non-imide (meth)acrylic compound is not particularlylimited provided that the (2) non-imide (meth)acrylic compound is acompound having at least one carbon-carbon double bond in its molecule.However, it is preferable that the (2) non-imide (meth)acrylic compoundhas two carbon-carbon double bonds in its molecule. In this case, it ispossible to attain easier photo polymerization. Further, it is morepreferable that the (2) non-imide (meth)acrylic compound is a compoundhaving, in its molecule, at least one ring that is an aromatic ring or ahetero ring. This arrangement causes the photosensitive film to beflowable in thermo-compression bonding, and to have a high resolution.

[0205] Especially, by such arrangement that a compound is used whosemolecule has a structure having 1 to 40 recurring units, preferably 6 to40 recurring unit represented by —(CHR⁴⁸CH₂—O)— (where R⁴⁸ is hydrogen,a methyl group, or an ethyl group), the monomer before curing becomesmore soluble in the alkali aqueous solution, which is the developer.Therefore, the resin that is not exposed to light becomes easier to bedissolved and removed with an alkaline aqueous solution, therebyattaining a good resolution in a shorter time.

[0206] Specifically, It is preferable that the compound is at least oneof di(meth)acrylate compounds having two aromatic rings Group (112):

[0207] (where each R⁴⁸ is independently a hydrogen atom, a methyl group,or an ethyl group, each R⁴⁹ is independently a divalent organic group,and each of r and s is independently an integer of 2 to 20).

[0208] Note that, if r and s are 0 or 1 in Group (112), the compositionwill have poor solubility in the alkali aqueous solution, thus resultingin failure of attaining a good development property. Moreover, it isdifficult to acquire a raw material for the composition in which r and sare 21 or more. Further, a photosensitive film produced from suchcomposition in which r and s are 21 or more, tends to be hygroscopic,even though the photosensitive film thus produced has a good solubilityin the alkali aqueous solution.

[0209] Specifically, for example, a (2) non-imide (meth)acrylic compoundmay be, but not limited to, bisphenol F EO modified (n=2 to 50)diacrylate, bisphenol A EO modified (n=2 to 50) diacrylate, bisphenol SEO modified (n=2 to 50) diacrylate, 1,6-hexandioldiacrylate,neopenthylglycoldiacrylate, ethyleneglycoldiacrylate,pentaerythritoldiacrylate, trimethylolpropanetriacrylate,pentaerithritoltriacrylate,dipentaerythritolhexaacrylatetetramethylolpropanetetraacr ylate,tetraethyleneglycoldiacrylate, 1,6-hexandioldimethacrylate,neopenthylglycodimethacrylate, ethyleneglycoldimethacryate,pentaerithritoldimethacryate, trime thylolpropanetrimethacrylatepentaerithritotrimethacrylate, dipentaerithritolhexamethacrylate,tetramethylolpropanetetramethacrylate,tetraethyleneglocoldimethacrylate, ethyleleglycoldimethacrylate,diethyleneglycoldimethacrylate, triethyleneglocoldimethacrylate,polyethyleneglocoldimethacrylate, 1,3-butyleneglycoldimethacrylate,1,6-hexandiodimethacrylate, polypropyleneglocoldimethacrylate,2-hydroxy-1,3-dimethachloxyethoxy)phenyl]propane, 2,2-bis[4-(methachloxyethoxy)phenyl] propane,2,2-bis[4-(methachloxy•diethoxy)phenyl]propane,2,2-bis[4-(methachloxy•polyethoxy)phenyl]propane,polyethyleneglycoldiacrylate, tripropyleneglycoldiacrylate,polypropyleneglocoldiacrylate, 2,2-bis [4-(acryloxy•diethoxy)phenyl]propane, 2,2-bis[4-(acryloxy•polyethoxy)phenyl] propane,2-hydroxy-1-acryloxy-3-methachloxypropane,trimethylolpropanetrimethacrylate, tetramethylolmethanetriacrylate,tetramethylo lmethane tetraacrylate, polypropyleneglocoldimethacrylate,1,4-butandioldimethacryalte, 3-methyl-1,5-pantandioldimethacrylate,1,6-mexanedioldimethacrylate, 1,9-nanondiolmethacrylate,2,4-diethyl-1,5-pentandioldimetharylate,1,4-cyclohexanedimethanoldimethacrylate, dipropyleneglocodiacrylatetricyclodecanedimethanoldiacrylate, 2,2-water-containing bis[4-(acryloxypolyethoxy)phenyl] propane, 2,2-bis [4-(acryloxy-polyproxy)phenyl]propane, 2,4-diethyl-1,5-pentandioldiacrylate, ethoxylatedtochimethylolpropanetriacrylate,propoxylatedtochimethylolpropanetriacrylate, isocyanulic triacrylate, isocyanulicdiacrylate, isocyanulic tri(ethaneacrylate), pentasulitoltetraacrylateethoxylatedpentasulitoltetraacrylate, and propoxylatedpentasulitoltetraacrylate, ditrimethylolpropanetetraacrylate,dipentaerithritolpolyacrylate, trially isocyanulate,glycidylmethacrylate, glycidylallylether,1,3,5-triacryloylhexahydro-s-triazine,4,4′-isopropylidenediphenoldimethacrylate, 4,4′-idopropylidenediphenoldiacrylate, methoxydiethyleneglycolmethacrylate,methoxylpolyethyleneglycolmethacrylate,β-methachloiloxyethylhydrogenphthalate,β-methachloiloxyethylhydrogensucynate,3-chloro-2-hydroxypropylmethacrylate, sutearylmethacrylate,phenoxyethylacrylate, phenoxydiethyleneglycolacrylate,phenoxypolyethyleneglocolacrylate, β-acryloyloxyethylhydroegensucynate,lauryl acrylate, triacryl 1,3,5-benzenecarboxylate, and the like.Moreover, those compounds may be used solely or in combination by usingtwo or more of them.

[0210] Moreover, it may be so arranged that a (meth)acrylic compoundother than the (meth)acrylic compounds listed above is added incombination with the (meth)acrylic compound listed above. The following(meth)acrylic compound other than the (meth)acrylic compounds listedabove may be added in combination with the above (meth)acrylic compound:triallyl-1,3,5-benzenecarboxylate, triallylamine, triallylcitrate,triallylphosphate, allobarbitone, diallylamine, diallydimethylsilane,diallyldisulfide, diallylether, diallylcyanate, diallylisophthalate,diallylterephthalate, 1,3,-diaryloxy-propanol, diallylsufide,diallylmaleate, and the like. The compounds may be used solely or incombination by using two or more of them.

[0211] Further, the present invention may be arranged such that acommercially-available (2) non-imide(meth)acrylate compound is used.Specifically, the commercially-available (2) non-imide(meth)acrylatecompound may be, for example, bisphenol A EO modified di(meth)acrylatesuch as allonix M210, M211B (both are product names, made by ToagoseiCo., Ltd.), NK ester ABE-300, A-BPE-4, A-BPE-10, A-BPE-20, A-BPE-30,BPE-100, and BPE-200 (all are product names, made by Shin-NakamuraChemical Co., Ltd.), and the like; bisphenol F PO modified (n=2 to 20)di(meth)acrylate such as allonix M-208 (product name, made by ToagoseiCo., Ltd.) and the like; bisphenol A PO modified (n=2 to 20)di(meth)acrylate such as dinacole acrylate DA-250 (made by Nagase KaseiCorp.), biscoate #540 (product name, made by Osaka Organic ChemicalIndustry Ltd.) and the like; and phthalic PO modified diacrylate such asdinacolacrylate DA-721 (product name, Nagase Kasei Corp.); and the like.

[0212] Furthermore, the present invention may be so arranged as tocontains an acylate such as (i) isocyanuric EO modified diacrylate suchas allonix M-215 (product name, Toagosei Co., Ltd.), (ii) isocyanuric EOmodified triacrylate such as allonix M-315 (product name, Toagosei Co.,Ltd.), NK ester A-9300 (product name, Shin-Namkamura Chemical Co., Ltd.and the like, even though the acrylate does not have an aromatic ring.The compounds may be used solely or in combination by using two or moreof them.

[0213] Moreover, for attaining an excellent flexibility in thephotosensitive film of the present invention, it is more preferable touse a modified di(meth)acrylate such as bis phenol F EO modifieddiacrylate, bis phenol A EO modified diacrylate, bis phenol S EOmodified diacrylate, bis phenol F EO modified dimethacrylate, bis phenolA EO modified dimethacrylate, and bis phenol S EO modifieddimethacrylate. Those compound may be used solely or in combination byusing two or more of them.

[0214] Especially, a compound in which 2 to 50 EO recurring units, whichis to be modified, are contained in one molecule of the modifieddi(meth)acrylate, is preferable. A compound in which 4 to 40 EOrecurring units are contained in one molecule of the modifieddi(meth)acrylate, is more preferable. The EO recurring units give bettersolubility in the alkali aqueous solution, thereby attaining a shorterdevelopment time. Note that, the heat resistance will become poor if thenumber of the EO recurring units exceeds 50. Thus, an arrangement inwhich the number of the EO recurring units exceeds 50 is not preferable.

[0215] In the photosensitive resin composition of the present invention,it is preferable that 1 part to 200 parts by weight of the modifieddi(meth)acrylate is added based on 100 parts by weight of the solublepolyimide. Further, it is more preferable that 3 parts to 150 parts byweight of the modified di(meth)acrylate is added based on 100 parts byweight of the soluble polyimide. If the amount of the modifieddi(meth)acrylate is above or below the range, there is a possibilitythat a targeted effect is not attained, or that the development propertyis adversely affected.

[0216] <Content (Amount in Composition)>

[0217] For both of the (1) (meth)acrylic compound and (2) (meth)acryliccompound, it is preferable that 1% to 200% by weight of the(meth)acrylic compound is added based on 100% by weight of the (A)soluble polyimide, whereas it is more preferable that 5% to 150% byweight of the (meth)acrylic compound is added based on the 100% byweight of the (A) soluble polyimide.

[0218] Especially, where a total amount of the (A) soluble polyimide and(B) (meth)acrylic compound is 100% by weight, it is preferable that (A)soluble polyimide is in a range of 30% to 70% by weight, and that, ofthe (B) (meth)acrylic compound, the imide(meth)acrylate compound is in arange of 5% to 60% by weight, the non-imide (meth)acrylic compound is ina range of 1% to 50% by weight.

[0219] Both in case where the range is based on the (A) solublepolyimide, and in case where the range is based on the total amount ofthe (A) soluble polyimide and the other component, an amount above orbelow the range, especially an amount below the lower limit, is notpreferable because such amount tends to result in a highthermo-compression-bondable temperature and a low resolution. On theother hand, the amount above the upper limit results in stickiness ofthe photosensitive film in a B stage condition. Further, the amountabove the upper limit tends to result in a fragility of a cured product.Thus, the amount above the upper limit is not preferable.

[0220] Moreover, as to the (B) (meth)acrylic compound, considering onlythe amount of the (1) imide (meth)acrylic compound to be added, theamount of the (1) imide (meth)acrylic compound is preferably in a rangeof 5% to 60% by weight, more preferably in a range of 5% to 40% byweight, further preferably in a range of 5 to 30% by weight, based on100% by weight of the total amount of the (A) soluble polyimide and the(B) (meth)acrylic compound. An amount less than 5% by weight tends tocause the cured photosensitive film to have a low fire retardingproperty. Thus, the amount less than 5% is not preferable. On the otherhand, an amount more than 60% by weight tends to cause thephotosensitive film to have a significant stickiness and poorresolution. Thus, the amount more than 60% by weight is not preferable.

[0221] Similarly, considering only (2) non-imide (meth)acrylic compound,the amount is preferably in a range of 1% to 50% by weight, morepreferably in a range of 1% to 40% by weight, and further preferably ina range of 5% to 10% by weight, based on 100% by weight of the totalamount of the (A) soluble polyimide and (B) (meth)acrylic compound. Anamount less than 1% by weight is not preferable because the amount lessthan 1% by weight tends to give a high thermo-compression-bondabletemperature and a poor resolution. On the other hand, an amount morethan 50% by weight results in stickiness of the film in the B stagecondition stage to be sticky, and allows the resin to ooze out easilyduring thermo-compression bonding. Further, the amount more than 50% byweight tends to result in over fragility of the cured product. Thus, theamount more than 50% by weight is not preferable.

[0222] In the present invention, (B) (meth)acrylic compound content inthe photosensitive resin composition or photosensitive film is notlimited to the ranges mentioned above, because the preferable rangesdepend on (i) which one of the (meth)acrylic compounds is used, (ii)which one of the other components is used, (iii) usage of the resultantphotosensitive resin composition or photosensitive film, (iv) and thelike factor. For example, it is possible to adjust the heat resistanceand thermo-compression-bondable temperature (later described) of thephotosensitive film by changing the content.

[0223] <(C) Photo Reaction Initiator>

[0224] Very preferable is an arrangement in which the photosensitiveresin composition and photosensitive film of the present inventioncontains a (C) photo reaction initiator. Especially, it is preferablethat the photosensitive resin composition and photosensitive film of thepresent invention contains, as the (C) photo reaction initiator, acompound that produces a radical by absorbing light whose wavelength isin a range of 400 nm to 450 nm.

[0225] A multi-purpose light-exposing device used is generally a mercurylamp, a metal halide lamp, or the like. Its light includes i ray (365nm), h ray (405 nm), or g ray (436 nm). The polyimide containing anaromatic tetracarboxylic dianhydride and an aromatic diamine absorbs iray by absorption caused by n conjugation. Therefore, it is verypreferable for the present invention to be so arranged as to use acombination of the polyimide with a photo reaction initiator capable ofefficiently producing a radical by the h ray and the g ray. Therefore,it is preferable to arrange the photosensitive resin composition andphotosensitive film of the present invention such that thephotosensitive resin composition and photosensitive film contain, inaddition to the (A) soluble polyimide and (B) (meth)acrylic compound, aphoto reaction initiator that produces a radical by absorbing awavelength in a range of 400 nm to 450 nm.

[0226] As one example of a compound that functions as the photo reactioninitiator and produces a radical by light of such a long length as longas the g ray and the i ray by light, acylphosphineoxide compounds may begiven, which are represented by the following Formulae (113) and (114).Radicals produced from the acylphosphineoxide compounds react with areactive group (vinyl, acroyl, methacroyl, allyl, and the like) havingtwo bonds, thereby accelerating the cross-linking reaction.

[0227] (where, in the formulae, each R⁶¹ is independently C₆H₅—,C₆H₄(CH₃)—, C₆H₂(CH₃)₂—, (CH₃)₃C—, C₆H₃ C₁₂—, and each R⁶² isindependently C₆H₅—, CH₃O-(methoxy group), CH₃CH₂O-(ethoxy group),C₆H₄(CH₃)—, and C₆H₂(CH₃)₂—).

[0228] Especially, the acylphosphineoxide represented by Formula (114)is preferred to the acylphosphineoxide represented by Formula (113),because the acylphosphineoxide represented by Formula (114) producesfour radicals by a-cleavage whereas the acylphosphineoxide representedby Formula (113) produces two radicals. These compounds may be usedsolely or in combination by using two or more of them.

[0229] In order to cure the epoxy group attached to the side chain ofthe polyimide resin, the carbon-carbon double bond, and thecarbon-carbon triple bond, the present invention may be so arranged asto use a photo reaction initiator of photo-cation-generating type,instead of the photo reaction initiator of radical-producing type.Specifically, for example, the photo reaction initiator ofphoto-cation-generating type may be diphenyliodinium compound salts suchas diphenyliodinium salt of dimethoxyanthraquinonesulfonic acid;triphenylsulphonium salts; pyrylium salts, triphenylonium salts;diazonium salts; and the like. These compounds may be used solely or incombination by using two or more of them. Here, it is preferable to mixtherein an aliphatic epoxy or a vinyl ether. The aliphatic epoxy andvinyl ether have a high cation curing property.

[0230] In order to cure the epoxy group attached to the side chain ofthe polyimide resin, the carbon-carbon double bond, and thecarbon-carbon triple bond, the present invention may be so arranged asto use a photo base generating agent (a photo reaction initiator ofphoto base generating type) as the photo reaction initiator.Specifically, for example, the photo reaction initiator of photo basegenerating type may be urethane compounds that are obtained by reactingan isocyanate with a nitrobenzylalcohol or a dinitobenzylalcohol;urethane compounds that are obtained by reacting an isocyanate with anitro-1-phenylethylalcohol or a dinitro-1-phenylethylalcohol; urethanecompounds that are obtained by reacting an isocyanate withdimethoxy-2-phenyl-2-propanol; and the like. Those compounds may be usedsolely or in combination by using two or more of them.

[0231] <Sensitizer (Pigment)>

[0232] In the present invention, it is preferable to use variousperoxides in combination as the photo reaction initiator. Especially inorder to attain a practically useful photosensitivity, it is speciallypreferable to use 3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenonewith a sensitizer (pigment) of various types.

[0233] The sensitizer (pigment) for use in the present invention may be,but not limited to, Michler's Ketone, bis-4,4′-diethylaminobenzophenone,benzophenone, camphorquinone, benzyl, 4,4′-dimethylaminobenzil,3,5-bis(diethylaminobenzilidene)-N-methyl-4-pyperidone,3,5-bis(dimethylaminobenzilidene)-N-methyl-4-piperidone,3,5-bis(diethylaminobenzilidene)-N-ethyl-4-piperidone,3,3′-carbonylbis(7-diethylamino)coumarin, riboflavintetrabutylate,2-methyl-1-[4-(methythio) phenyl]-2-mopholinopropane-1-one,2,4-dimethylthioxanthone, 2,4-diethylthioxathaone,2,4-diisopropylthioxanthone, 3,5-dimethylthioxanthone,3,5-diisopropylthioxanthone,1-phenyl-2-(ethoxycarbonyl)oxyiminopropan-1-one, benzoinether,benzoinisopropylether, benzanthrone, 5-nitroacenaphthene,2-nitrofluorene, anthrone, 1,2-benzanthraquinone,1-phenyl-5-mercapto-1H-tetrazol, thioxanthen-9-on, 10-thioxanthenone,3-acethylindole, 2,6-di(p-dimethylaminobenzal)-4-carboxycyclohexanone,2,6-di(p-dimethylaminobenzal)-4-hydroxycyclohexanone,2,6-di(p-diethylaminobenzal)-4-carboxycyclohexanone,2,6-di(p-diethylaminobenzal)-4-hydroxycyclohexanone,4,6-dimethyl-7-ethylaminocoumarin, 7-diethylamino-4-methylcoumarin,7-diethylamino-3-(1-methylbenzoimidazoril)coumarin,3-(2-benzoimidazoril)-7-diethylaminocoumarin,3-(2-benzothiazoril)-7-diethylaminocoumarin,2-(p-dimethylaminostyryl)benzoxyazol, 2-(p-dimethylaminostyryl)quinoline, 4-(p-dime thylamino styryl) quinoline,2-(p-dimethylaminostyryl)benzothiazol,2-(p-dimethylaminostyryl)-3,3-dimethyl-3H-indole, and the like. Thesecompounds may be used solely or in combination by using two or more ofthem.

[0234] Of these compounds, especially preferable sensitizers arebis-4,4′-dialkylaminobenzophenone derivatives, such asbis-4,4′diethylaminobenzophenone and the like, and coumarine derivativessuch as 3,3′-carbonylbis(7-diethylamino)coumarine and the like.

[0235] <Photo Polymerization Auxiliary Agent>

[0236] Moreover, in order to attain practically useful photosensitivity,the present invention may be arranged such that the photo reactioninitiator is used in combination with a photo polymerization auxiliaryagent. For example, the photo polymerization auxiliary agent may be, butnot limited to, 4-diethylaminoethylbenzoate,4-dimethylaminoethylbenzoate, 4-diethylaminoburopyl benzoate,4-dimethylaminopropylbenzoate, 4-dimethylaminoisoamilbenzoate,N-phenylglycine, N-methyl-N-phenylglycine, N-(4-cyanophenyl)glycine,4-dimethylaminobenzonitril, ethyleneglycoldithioglycolate,ethyleneglycoldi(3-mercaptopropyonate), trimethyrolpropanethioglycolate,trimethyrolpropanetri(3-mercaptopropyorate),pentaerithritoltetrathioglycolate, pentaerithritoltetra(3-mercaptopropryonate), trimethyrol ethanetrithioglycolate,trimethyrolpropanetrithioglycolate,trimethyrolethanetri(3-mercaptopropyonate),dipentaerithritolhexa(3-mercaptopropyonate), thioglycol acid,α-mercaptopropyonic acid, t-butylperoxybenzoate,t-butyperoxymethoxypenzoate, t-butyperoxynitrobenzoate,t-butyperoxyethybenzoate, phenyisopropylperoxybenzoate,di-t-butyldiperoxyisophthalate tri-t-butyltriperoxytrimeritatetri-t-butyltriperoxytrimeritate, tetra-t-butyltetraperoxypyromeritate2,5-dimethyl-2,5-di(benzoil peroxy)hexane, 3,3′,4,4′-tetra(t-butylperoxycarbonyl) penzophenone, 3,3′,4,4′-tetra(t-amylperoxycarbonyl) benzophenone, 3,3′,4,4′-tetra(t-hexylperoxycarbonyl) benzophenone,2,6-di(p-azidobenzal)-4-hyroxycyclohexane, 2,6-di(p-azidobenzal)-4-carboxycyclohexanone, 2,6-di(p-azidobenzal)-4-methoxycyclohexanone,2,6-di(p-azidobenzal)-4-hydroxymethylcyclohexanone,3,5-di(p-azidobenzal)-1-methyl-4-piperidone,3,5-di(p-azidobenzal)-4-piperidone,3,5-di(p-azibenzal)-N-acetyl-4-piperidone,3,5-di(p-azidobenzal)-N-methoxylcarbony-4-piperidone,2,6-di(p-azidobenzal)-4-hydroxycyclohexanone,2,6-di(m-azidobenzal)-4-carboxycyclohexanone,2,6-di(m-azidobenzal)-4-methoxycyclohexanone,2,6-di(m-azidobenzal)-4-hydroxymethylcyclohexanone,3,5-di(m-azidobenzal)-N-methyl-4-piperidone,3,5-di(m-azidobenzal)-4-piperidone,3,5-di(m-azidobenzal)-N-acetyl-4-pyperidone,3,5-di(m-azidobenzal)-N-methoxycarbonyl-4-piperidone,2,6-di(p-azidocinnamylidene)-4-hyrdoxycyclohexanone,2,6-di(p-azidocinnamylidene)-4-carboxycyclohexanone,2,6-di(p-azidocinnamylidene)-4-cyclohexanone,3,5-di(p-azidocinnamylidene)-N-methyl-4-piperidone,4,4′-diazidochalcone, 3,3′-diazidochalcone, 3,4′-azidochalcone,4,3′-diazidochalcone, 1,3-diphenyl-1,2,3-propanetrione-2(o-acetyl)oxime,1,3-diphenyl-1,2,3-propanetrione-2-(o-n-propylcarbonyl) oxime,1,3-diphenyl-1,2,3-propanetrione-2-(o-methoxycarbonyl)oxime,1,3-diphenyl-1,2,3-propanetrione-2-(o-ethoxycarbonyl)oxide,1,3-diphenyl-1,2,3-propanetrione-2-(o-benzoil)oxime,1,3-diphenyl-1,2,3-propanetrione-2-(o-phenyloxycarbonyl) oxime,1,3-bis(p-methylphenyl)-1,2,3-propanetrione -2-(o-benzoil)oxime,1,3-bis(p-methoxyphenyl)-1,2,3-propanetrione-2-(o-ethoxycarbonyl)oxime,1-(p-methoxy phenyl)-3-(p-nitrophenyl)-1,2,3-propanetrione-2-(o-phenyloxicarbonyl)oxide, and the like. Moreover, as another auxiliary agent,it may be so arranged that a trialkylamine is mixed in. Thetrialkylamine may be triethylamine, tributylamine, triethanolamine, andthe like. These compounds may be used solely or in combination by usingtwo or more of them.

[0237] As described above, the (C) photo reaction initiator of thepresent invention is so arranged as to be at least one of the compoundof the radical-producing type, the compound of the photo cationproducing type, and the compound of the photo base producing type.Furthermore, the present invention may be so arranged that the (C) photoreaction initiator is used in combination with the sensitizer (pigment)and/or the photo polymerization auxiliary agent. Therefore, in thepresent invention, the term “the (C) photo reaction initiator” denotes,in a broad sense, not only the photo reaction initiators in a narrowsense (the three types of photo reaction initiators (theradical-producing type, photo-cation-producing type,photo-base-producing type), but also the combination of the photoreaction initiator and a sensitizer (pigment and/or the photopolymerization auxiliary agent).

[0238] As a preferable example of the (C) photo reaction initiator ofthe present invention, the (C) photo reaction initiator may be anacylphosphineoxide compound, besides the combination use of3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone and the sensitizer.

[0239] <(C) Photo Reaction Initiator Content (An Amount of the (C) PhotoReaction Initiator in Composition)>

[0240] A total amount of the photo reaction initiator and the sensitizerand the like (that is the amount of the (C) photo reaction initiator inthe broad sense in the composition) is preferably in a range of 0.001%to 15% by weight, more preferably in a range of 0.001% to 10% by weight,further preferably in a range of 0.01% to 10% by weight, and especiallypreferably in a range of 0.01% to 5% by weight, based on 100% by weightof a total weight of the (A) soluble polyimide, (B) (meth)acryliccompound, and (D) fire retardant. If the amount is out of the range of0.001% to 15% by weight, there is a possibility that sensitizing effectis not obtained or the development property is adversely affected.

[0241] Moreover, considering the sensitizer alone, an amount of thesensitizer to be mixed in is preferably in a range of 0.1 part to 50parts by weight, and further preferably in a range of 0.3 parts to 20parts by weight, based on 100 parts by weight of the (A) solublepolyimide. If the amount of the sensitizer is out of the range, there isa possibility that sensitizing effect is not obtained or the developmentproperty is adversely affected.

[0242] Furthermore, considering the photo polymerization auxiliary agentalone, an amount of the photo polymerization auxiliary agent to be mixedin is preferably in a range of 0.1 part to 50 parts by weight, andfurther preferably in a range of 0.3 parts to 20 parts by weight, basedon 100 parts by weight of soluble polyimide. If the amount of the photopolymerization auxiliary agent is out of the range, there is apossibility that a desired sensitizing effect is not obtained or thedevelopment property is adversely affected.

[0243] <(D) Fire Retardant>

[0244] It is preferable that the photosensitive resin composition andphotosensitive film of the present invention contains (D) fireretardant.

[0245] The photosensitive resin composition, photosensitive film, andlaminate of the present invention are suitable for use in electronicparts, as described above, even though usage of the photosensitive resincomposition, photosensitive film, and laminate of the present inventionis not limited to this. Here, there is fire retardant regulation for theelectric/electronic parts. Specifically, for example, an FPC and a headpart of the hard disc apparatus are exposed to a high temperature for along time. Because of this, there is a possibility that the FPC and thehead part of the hard disc apparatus causes inflammation. Therefore, acover lay film and the like for use in those electric/electronic partsshould have a high flame resistance. Thus, it is preferable that thephotosensitive resin composition and photosensitive film become fireresistant after being cured.

[0246] The (D) fire retardant used in the present invention is notparticularly limited. Preferably, the (D) fire retardant may be at leastone of (i) a halogen compound having a halogen atom in its structure,(ii) a phosphorus compound having a phosphorus atom in its structure,and a siloxane compound having a siloxane structure in its structure. Inthe other words, it is preferable that the (D) fire retardant used inthe present invention is a compound to which at least one kind ofatom/or site is covalent-bonded, the at least one kind atom/or a sitebeing selected from a group consisting of halogen, phosphorus, andsiloxane bonding.

[0247] As to the halogen compound, for effectively attaining the flameresistance, the halogen content in the compound is preferably 15% ormore by weight, more preferably 20% or more by weight, furtherpreferably 30% or more by weight, especially preferably 40% or more byweight, and most preferably 50% or more. Particularly, a compound inwhich chlorine or bromine is contained is used in general.

[0248] As to the phosphorus compound, for effectively attaining theflame resistance, phosphorus content in the compound is preferably 5.0or more by weight, and more preferably 7.0% or more by weight.

[0249] As to the siloxane compound, for effectively attaining the heatresistance and flame resistance, it is preferable that the siloxanecompound is a organopolysiloxane compound (phenyl siloxane compound)having aromatic rings in a high ratio.

[0250] <Halogen Compound as the Fire Retardant>

[0251] In case where the halogen compound is used among the (D) fireretardants for use in the present invention, it is possible topreferably arrange such that the (D) fire retardant is a halogen-type(meth)acryl compound having at least one aromatic ring and at least onecarbon-carbon double bond. Specifically, it is preferable that at leastone of the compounds, which are selected from the halogen-type(meth)acrylic compound in Group (115), is contained:

[0252] (where R⁵¹ is a halogen atom, each R⁵² is independently ahydrogen atom or a methyl group, t is an integer of from 0 to 10, u isan integer of from 1 to 5, and v is an integer of 1 to 4).

[0253] All of the halogen-type (meth)acrylic compounds has a reactivegroup for curing, and an advantage that they can give the heatresistance and the flame resistance at the same time.

[0254] The halogen contained in the halogen compound used in the presentinvention may be chlorine, bromine, or the like. For attaining the flameresistance, bromine is preferable. That is, it is preferable that thehalogen compound used in the present invention is a bromine containingcompound. Especially, the halogen-type (meth)acrylic compounds in Group(115) and the like that contain three or more bromines in its moleculeare preferable. For attaining a better fire resistance, a higher brominecontent is more preferable.

[0255] Specifically, examples of the bromine-containing (meth)acrylcompound represented by Group (115) are bromide-based monomers, such asnew frontier BR-30 (tribromophenylacrylate), BR-30M(tribromophenylmethacrylate, BR-31 (EO modified tribromophenylacrylate),BR-42M (EO modified tetrabromo bisphenol A dimethacrylate) (all are madeby Dai-Ichi Kogyo Seiyaku Co., Ltd.) and the like; brominated aromatictriazines, such as pyroguard SR-245 (made by Dai-Ichi Kogyo Seiyaku Co.,Ltd.) and the like; brominated aromatic polymers, such as pyroguardSR-250, SR-400A (made by Dai-Ichi Kogyo Seiyaku Co., Ltd.); brominatedaromatic compounds such pyroguard SR-990A) as made by Dai-Ichi KogyoSeiyaku Co., Ltd.) and the like; and the like. These compounds may beused solely or in combination by using two or more of them. Note that ahalogen compound having no carbon-carbon double bond may be usedsimilarly, because addition of such halogen compound can give the flameresistance.

[0256] Moreover, the halogen compound of the present invention may be aphosphorus compound having a halogen atom in its molecule. Specifically,examples of the halogen compound are halogen-containing ester phosphateand the like, such as CLP (tris(2-chloroethyl)phosphate), TMCPP(tris(chloroprophyl)phosphate), CRP (tris(dichloropropyl)phosphate),CR-900(tris(tribromoneobenzy)phosphate) (all are made by DaihachiChemical Industry Co., Ltd.), and the like. These compounds may be usedsolely or in combination by using two or more of them.

[0257] Furthermore, in case where the halogen compound is used as the(D) fire retardant, addition of at least one of antimony trioxide andantimony pentoxide (hereinafter, referred to as antimony oxidecollectively) produces an antimony halide because the antimony oxidedraws out the halogen atom from the fire retardant around a temperatureat which the resin starts to be thermolyzed. Thus, the addition of theantimony oxide improves the flame resistance synergistically.

[0258] The amount of the antimony oxide to add in is not particularlylimited. However, it is preferable that the amount of the antimony oxideto be added is preferable in a range of 0.1% to 10% by weight based on100% by weight of the total amount of the (A) soluble polyimide, (B)(meth)acrylic compound, (D) fire retardant. It is more preferable thatthe amount of the antimony oxide to be added is in a range of 1% to 6%by weight, based on 100% by weight of the total amount.

[0259] Here, it is especially preferable that the phosphorus compoundand the siloxane compound are used as the (D) fire retardant of thepresent invention.

[0260] Recently, the flame resistance regulation for theelectric/electronic parts requires not only the retardation andprevention of inflammation but also non-pollution-causing property, lowtoxicity, and safety, as the concern about the world-wide environmentalproblem and safety for human body is increased. Thus, the flameresistance regulation requires not only being difficult to be combusted,but also reduction in toxic gas generated by heat, and insmoke-generating substance.

[0261] In the insulating resin and the solder resist (typical example ofwhich is the cover lay film) for printed wiring board), most the halogencompounds used as the fire retardant are bromine-type, conventionally.Widely used are brominated epoxy resin, a typical example of which istetrabromo bis phenol A. However, the fire retardant including a halogengives a bad effect on the environment. Thus, replacing the bromine-typefire retardant with non-halogen type fire retardant has been considered.

[0262] The non-halogen type fire retardant may be a nitrogen typecompound, a phosphorus type compound, an inorganic type compound, or thelike. In general, the nitrogen type compound affects the curing of theresin, whereas the phosphorus type resin causes lower moistureresistance and the like drawback. Therefore, there is conventionally alimit in selection of the flame resistant raw material to be used in thecover lay film that requires the electronic insulating property andresistance against hydrolysis.

[0263] Moreover, recently, use of the siloxane compound as the fireretardant has been studied. However, there is a large limit in type ofthe resin capable of showing flame resistance effect. Further, there isa very few type of siloxane compounds that show a large flame resistanceeffect by sole use thereof. Even a siloxane compound that relativelyhigh flame resistance effect, needs to be added in a large amount inorder to satisfy the strict flame resistance standard. As a result, theaddition of the siloxane compound gives adverse effects on theproperties of the photosensitive resin composition, whiledisadvantageously increasing the cost. Thus, the addition of thesiloxane compound is not practical.

[0264] On the other hand, the phosphorus compound and the siloxanecompound used in the present invention have excellent usefulness (forexample, use of the phosphorus compound and the siloxane compound doesnot affect the properties of the photosensitive resin composition).Therefore, the use of the phosphorus compound and the siloxane compoundfurther improves quality of the photosensitive resin composition andphotosensitive film of the present invention.

[0265] <Phosphorus Compound as (D) Fire Retardant>

[0266] In case where the phosphorus compound is used among the (D) fireretardants for use in the present invention, a type of the compound isnot particularly limited. Especially, the phosphorus compound may be (1)a compound selected from ester phosphate (including condensed esterphosphate), phosphorus ester, phosphine, and phosphineoxide, or (2) acompound whose 10%-weight-loss temperature is in range of 300° C. to500° C., and which has both a phosphorus atom and a nitrogen atom in itsmolecule (phosphorus-nitrogen compound). <Phosphorus compound (1)>

[0267] Of the phosphorus compounds, especially, ester phosphate(including condensed ester phosphate), and phosphineoxide are preferablyused, because ester phosphate and phosphineoxide are highly compatiblewith the soluble polyimide.

[0268] As to the ester phosphate, it is more desirable that the esterphosphate has at least one aromatic ring, because the ester phosphatehaving at least one aromatic ring can attain the fire retardation andhas an excellent hydrolysis resistance. It is further preferable thatthe ester phosphate has two or more aromatic rings. Specifically, forexample, it is preferable that the ester phosphate is a ester phosphateselected from the following Group (116):

[0269] (where R⁵³ is a methyl group, R⁵⁴ is an alkyl group or a phenylgroup, R⁵⁵ is a divalent organic group, w is an integer from 0 to 3, xand y are integers satisfying x+y=3). It is further preferable that theester phosphate has two or more aromatic ring. Such ester phosphatecompound is soluble in the alkali aqueous solution. Thus, when using theester phosphate as a raw material of the photosensitive cover lay film,it is possible to perform the development with the alkali aqueoussolution.

[0270] Specifically, examples of the phosphorus compound are: esterphosphates such as TPP (triphenylphosphate), TCP (tricresilphosphate),TXP (trixylenylphosphate), CDP (cresildiphenylphosphate), PX-110 (cresil2,6-xylenylphosphte) (all are made by Daihachi Chemical Industry Co.,Ltd.); non-halogen condensed ester phosphates such as CR-733(resosinoldiphosphate), CR-741, CR-747, PX-200) (all are made byDaihachi Chemical Industry Co., Ltd.); phosphoric (meth)acrylates suchas biscoat V3PA (made by Osaka Organic Chemical Industry Ltd.), MR-260(made by Daihachi Chemical Industry Co., Ltd.) and the like; phosphorousester such as phosphorous tri phenyl ester and the like. Those compoundsmay be used solely or in combination by using two or more of them.

[0271] In terms of the hydrolysis resistance, the phosphorous compoundis easy to be hydrolyzed under a high-pressure and high-humid condition.The use of the condensed ester phosphate makes it possible to attainboth the flame resistance and hydrolysis resistance. Moreover, thecombinative use of the bromine compound and the phosphorous compound asthe fire retardant makes it possible to realize the flame resistance ofthe cured photosensitive film with a little amount of fire retardant bythe synergistic effect of the combinative use.

[0272] Note that well known compounds may be used as the others of thephosphorus compounds (1). Moreover, the phosphorus compounds (1)containing ester phosphate may be used solely or in combination by usingtwo or more of them.

[0273] <Phosphorus compound (2)>

[0274] The phosphorous compound (2) (phosphorus-nitrogen compound) isused preferably because, in combusting, the phosphorus atom has adehydration effect and inert gas is produced from the nitrogen atom,thereby attaining flame resistance by synergistic effect. Note that the“10% weight loss temperature” is a temperature at which a weight of asample is reduced by 10%, the weight being measured in air by using adifferential scanning calorimeter (made by Seiko Corp./DTA 220) atrising temperature from 20° C. to 600° C. at a rate of 20° C./minute.

[0275] In the present invention, if the phosphorus compound (2) has a10% mass loss temperature lower than 300° C., the phosphorus compoundhas an excessively low thermolysis temperature or vaporizationtemperature. Thus, the 10% mass loss temperature lower than 300° C. isnot preferable. On the other hand, if the phosphorus compound (2) has a10% mass loss temperature higher than 500° C., the phosphorus compoundhas an excessively high thermolysis temperature or vaporizationtemperature. The excessively high thermolysis temperature orvaporization temperature causes insufficient flame resistance effect.Thus, the phosphorus compound (2) has a 10% mass loss temperature higherthan 500° C. is not preferable.

[0276] A compound selected from phosphazen compounds, phosphoricmelamines, polyphosphoric melamines, ammonium phosphates, and ammoniumpolyphosphates, may be preferably used as the phosphorus compound (2).Those phosphorus compounds (2) may be used solely or in combination byusing two or more of them.

[0277] By using the phosphorus compound (2), it is possible to attain,without using the halogen compound, the cured photosensitive film havingthe flame resistance and high soldering heat resistance. Moreover, it ispossible to give thermo flowability to the photosensitive film in the Bstage condition.

[0278] <Phosphazen Compound>

[0279] Among the phosphorus compounds (2), because of its heatresistance, hydrolysis resistance, flame resistance, and chemicalresistance, the phosphazen may be preferably a cyclophosphazen compoundrepresented by Formula (20):

[0280] (where each R⁵ is independently a hydrogen atom or a monovalentorganic group having no halogen, and q is an integer from 3 to 30).

[0281] It is preferable that the organic group R⁵ in Formula (20) is anorganic group which forms a bonding with a phosphorus atom via —O—, —S—,—NH—, —NR— (R is a monovalent organic group). Specific examples of suchorganic groups are: vinylether groups, styrene ether groups, alcoxygroups, phenoxy groups, amino groups, allyl groups and the like. Ofthose groups, it is preferable that the organic group X is a phenoxygroup.

[0282] Specifically, the compound may be diphenoxy phosphazen,phenoxyisopropoxy phosphazen, amide phosphazen, or the like. Ascommercially available products, SP-100, SPS-100, SPD-100, SPE-100,S-134 (which are all made by Otsuka Chemical Co., Ltd.), and the likemay be used as this compound. These compounds may be used solely or incombination by using two or more of them.

[0283] Moreover, the phosphazen compound that can be used suitably inthe present invention may be a phosphazen compound having, as R⁵ inFormula (20), a substituent or substituents of one or more of typesselected from vinyl group, allyl group, methallyl group, and 1-butenylgroup. Preferably, the phosphazen compound that can be used suitably inthe present invention may be a phosphazen compound having, as R⁵ inFormula (20), an allyl group that is a reactive substituent. Moreover,it is possible to arrange such that a phosphazen copolymer of having, inFormula (20), a different polymerization degree n of the phosphazencompound.

[0284] Specific examples of the phosphazen compound having the reactivesubstituent are: bis(2-allylphenoxy)phosphazen,bis(2-methoxy-4-allylphenoxy)phosphazen, phenoxyallyl phosphazen, or thelike. These compounds may be used solely or in combination by using twoor more of them.

[0285] The use of the phosphazen compound as the phosphorus compound (2)gives the cured photosensitive film an excellent electric insulatingproperty as well as the fire resistant property. Moreover, it is morepreferable to use the phosphazen compound, because the use of aphosphoric melamine, a polyphosphoric melamine, ammonium phosphate, orammonium polyphosphate cannot give an excellent electric insulatingproperty, while they are excellent in giving the cured photosensitivefilm the fire resistant property.

[0286] <Phosphoric Melamine/Polyphosphoric Melamine>

[0287] Next, phosphoric melamines are compounds in which phosphoric acidis bound with melamine in various ratio. Also referred to as aphosphoric melamine is a compound in which phosphoric acid is boundwith, not only melamine, but also a nitrogen-containing compound such asammonia, amide, ethylenediamine, and the like, or metals such asaluminum, magnesium, calcium and the like, provided that majority of theparts is bound with melamine.

[0288] For example, the following compounds may be used as thephosphoric melamine in the present invention: product name: P-7202 (madeby Sanwa Chemical Corp.), Fyrol MP (Registered Trademark; made by AkzoNovel K.K.), anitblaze NH (Registered Trademark; made by Albright &Wilson Corp.), melapur MP (Registered Trademark; made by N. V. DSM.),and the like. These compounds may be used solely or in combination byusing two or more of them.

[0289] Further, the polyphosphoric melamines are compounds in whichpolyphosphoric acid (dehydrated condensation product of a polymer ofphosphoric acid that is a trimer or a greater polymer) is bound withmelamine in various ratios. It is possible to use the polyphosphoricmelamines with no particular limitation in their condensation degrees ofpolyphosphoric acid, and primary molecular structures such as whether aring or a chain. Also referred to as a polyphosphoric melamine is acompound in which not all of unit structures of phosphoric acid arebound with melamine, and some of melamine molecules are substituted witha nitrogen-containing compound such as an ammonia, an amide, anethylenediamine, or the like, or a metal such as aluminum, magnesium,calcium or the like, provided that majority of the parts is bound withmelamine.

[0290] For example, the following compounds may be used as thepolyphosphoric melamine in the present invention: product name: MPP-A(made by Sanwa Chemical Corp.), PMP-100 (Made by Nissan ChemicalIndustries Ltd.), melapur 200 (Registered Trademark; made by N. V.DSM.), and the like. These compounds may be used solely or incombination by using two or more of them.

[0291] <Ammonium Phosphate/Ammonium Polyphosphate>

[0292] The ammonium phosphates are compounds in which phosphoric acid isbound with ammonia. Moreover, ammonium polyphosphates are compounds inwhich polyphosphoric acid is bound with ammonia in various ratios. Againit is possible to use the ammonium polyphosphates with no particularlimitation in their condensation degrees of polyphosphoric acid, andprimary molecular structures such as whether a ring or a chain.

[0293] Also referred to as an ammonium polyphosphate is a compound inwhich not all of unit structures of phosphoric acid are bound withammonia, and some of ammonia molecules are substituted with anitrogen-containing compound such as a melamine, an amide, anethylenediamine, or the like, or a metal such as aluminum, magnesium,calcium or the like, provided that majority of the parts is bound withammonia.

[0294] For example, the following compounds may be used as the ammoniumpolyphosphate in the present invention: product name: sumisafe P(Registered Trademark, made by Sumitomo Chemical Co., Ltd.), sumisafe PM(Registered Trademark, made by Sumitomo Chemical Co., Ltd.), teraju C60(Registered Trademark, made by Chisso Corp.), FCP-700 (made by SuzuhiraChemical Co., Ltd.), taien S (made by Taihei Chemicals Ltd.), nonenenPR-62 (made by Marubishi Yuka Industry Corp.), exolit AP422 (RegisteredTrademark, made by Clariant Ltd.), exolit AP462 (Registered Trademark,made by Clariant Ltd.), phos-chek P30 (Registered Trademark, made bySolutia Inc.), and the like. These compounds may be used solely or incombination by using two or more of them.

[0295] Ammonium polyphosphate improves heat resistance when used incombination with a triazine-based condensated nitrogen-containingcompound. Thus, the use of ammonium polyphosphate gives betterhydrolysis resistance when applied by using a special surface-coatingmethod.

[0296] <Siloxane Compound as (D) Fire Retardant>

[0297] In case where the siloxane compound among the fire retardantsusable in the present invention is employed, it is preferable that thesiloxane compound is an organopoly siloxane compound having an aromaticring (phenyl group) in a high ratio, that is, a phenyl siloxanecompound.

[0298] With respect to all organic substituests, the phenyl siloxanecompound contains an aromatic group by 10% or more, preferably 20% ormore, and preferably 25% or more. The higher the aromatic group content,the greater the flame resistance effect. Thus, a higher aromatic groupcontent is desirable.

[0299] The use of an oraganopoly siloxane compound having a low aromaticgroup content tends to cause deterioration in dispersibility andmiscibility of the (D) fire retardant with respect to (A) solublepolyimide and (B) (meth)acrylic compound. In this case, film-likeformation of the photosensitive resin composition tends to result in alow transparent film due to phase separation of plural components havingdifferent refraction indexes is caused, or non-transparent film.

[0300] Moreover, in case where an organopoly siloxane compound having alow aromatic group content is used, it is difficult to attain asufficient fire resistant effect without adding a larger amount of theorganopoly siloxane compound. However, the addition of the larger amountof the organopoly siloxane compound tends to result in a significantdeterioration of various properties (for example, mechanical strength)of the cured photosensitive film.

[0301] <Specific Example of Siloxane Compound>

[0302] The phenyl siloxane compound, which is a kind of silicone resin,has a structure formed by polymerization of at least one of thefollowing M unit (one-functional-group-containing siloxane unit), D unit(two-functional-group-containing siloxane unit), T unit(three-functional-group-containing siloxane unit), and Q unit(four-functional-group-containing siloxane unit): M unit:

[0303] (where R⁶ is an organic group), D unit:

[0304] (where R⁶ is an organic group), T unit:

[0305] (where R⁶ is an organic group), Q unit:

[0306] There is no particular limitation in the siloxane compound usableas the fire retardant in the present invention. Especially, it ispreferable to use, as the fire retardant, at least one of (1) a siloxanecompound having at least one of the T unit and Q unit, and (2) asiloxane compound having the D unit.

[0307] Note that in each unit the organic group R⁶ is not particularlylimited, and may be identical with or different from each other.Specifically, R⁶ may be alkyl groups such as methyl group, ethyl group,propyl group, butyl group, pentyl group, hexyl group, heptyl group,octyl group, and the like; cycloalkyl groups such as cyclohexyl groupand the like; alkenyl groups such as vinyl group, (meth)acryl group,allyl group, and the like; aryl groups such as phenol group, stylylgroup, phenyl group, tolyl group, biphenyl group, naphthyl group, andthe like; alkoxy groups, polyether groups, epoxy groups, hydroxyl group,carboxyl group, amino group, and monovalent organic groups prepared bysubstituting, with a halogen atom, cyano group, or the like, part or allof hydrogen atoms bound with a carbon atom(s) of those groups; and thelike. The siloxane compound of the present invention may contain onlyone of those organic group or may contain two or more of those organicgroups.

[0308] <Siloxane Compound (1)>

[0309] In case of the siloxane compound (1), the siloxane (1), which hasa branched structure, can give a good flame resistance. Especially, itis preferable that the siloxane compound (1) has the T unit.

[0310] As to the siloxane compound (1), it is preferable that thesiloxane (1) contains the T and Q units (branch unit) by 20 mol % orhigher based on a total amount of a siloxane unit. An amount of the Tand Q units less than 20 mol % causes the siloxane compound to have alow heat resistance, thereby deteriorating the effect of the flameresistance. Moreover, the amount of the T and Q units less than 20 mol %causes the siloxane compound to have an excessively low viscosity. Incase of the production of siloxane compound, a silicone compound flowsout on a surface of the photosensitive film.

[0311] Further, the siloxane compound (1) contains the branch unitpreferably in a ratio of 30 mol % or more and 95 mol % or less withrespect to the total amount of the siloxane unit. If the ratio is 30 mol% or more, further improved heat resistance of (B) component: siliconecompound is attained, and thus a cover lay film containing this has alargely improved flame resistance. However, if the ratio exceeds 95 Mol%, a silicone main chain has a low degree of freedom. There is apossibility that such a low degree of freedom in the silicone main chainmakes it difficult to cause condensation of the aromatic group incombustion, thereby making it difficult to attain a remarkable flameresistance. As described above, it is preferable that 20 mol % or moreof the organic groups contained in the siloxane compound (1) is thearomatic group. If the ratio of the aromatic group contained in thesiloxane compound (1) is below the range, there is a possibility that anaromatic group-aromatic group condensation becomes difficult to takeplace in combustion, thereby causing a low flame resistance effect.

[0312] A lowest limit of the ratio of the aromatic group in the organicgroups contained is 20 mol %, preferably 40 mol % or higher, and morepreferably 60 mol % or higher. On the other hand, a highest limit of theratio is 95 mol % or lower, and preferably 90 mol % or lower. A mostpreferable range of the ratio of the aromatic group in the organicgroups contained is 60 mol % or higher and 85 mol % or lower.

[0313] Especially, it is preferable that a structural unit in which R⁶in the T unit is the aromatic group, shares 20 mol % or more, based on100 mol % of the T unit. It is preferable that R⁶ in the T unit is aphenyl group.

[0314] As long as the ratio is within the range of from 40 mol % to 85mol %, it is possible to attain more efficient condensation of thearomatic group in combustion and a good miscibility of the siloxanecompound (1) with respect to the (A) soluble polyimide. The goodmiscibility of the siloxane compound (1) improves the dispersibility.Thus, as long as the ratio is within the range of from 40 mol % to 85mol %, it is possible to attain a very good flame resistant effect.However, if the ratio exceeds 95 mol %, there is a possibility thataromatic group-aromatic group steric hindrance would result indifficulty in the condensation of them, thereby making it difficult toattain a remarkable flame resistance. The aromatic group contained inthe siloxane compound (1) may be a phenyl group, a biphenyl group,naphthalene, or their derivatives. In consideration of safety of thesiloxane compound, the phenyl group is especially preferable.

[0315] Moreover, of the groups that are contained in the siloxane andare attached to the main chain or the side chain branched therefrom, themethyl group is preferable apart from the aromatic group. Further, aterminal group is a functional group of at least one kind selected fromthe group consisting of methyl group, phenyl group, hydroxyl group,alcoxy group, vinyl group, and (meth)acryl group. In the arrangement inwhich the terminal group has those functional groups, photosensitiveresin composition unlikely occurs in mixing the (A) soluble polyimide,and the siloxane compound. Thus, it is possible to attain evendispersion. Therefore, it is possible to realize, after curing, furtherbetter flame resistance and heat resistance without deteriorating theouter appearance of the photosensitive film.

[0316] Especially, it is more preferable that the terminal group of thesiloxane compound (1) is a functional group of at least one kindselected from the group consisting of vinyl group and (meth)acryl group.That is, it is preferable that the terminal group of the siloxanecompound having the branched structure is at least one of vinyl groupand (meth)acryl group. By arranging such that the siloxane compound,which is the (D) fire retardant, is a compound whose terminal group is acompound having a reactive carbon-carbon unsaturated bond, it ispossible to cause, during photo curing and thermal curing,copolymerization of the siloxane compound with the (B) (meth)acryliccompound used in the present invention. Therefore, it is possible toattain better flame resistance and heat resistance of the photosensitivefilm after curing, and to prevent the siloxane compound from beingdissolved out of the exposed film during the development treatment. Incase of a photosensitive film in which a siloxane compound whoseterminal group is a compound having no reactive carbon-carbonunsaturated bond, there is a possibility that the siloxane compound isdissolved into the developer during the development treatment, therebycausing the cured film to have a low flame resistance.

[0317] Moreover, there is no particular limitation in the averagemolecular weight (weight average molecular weight) of the siloxanecompound. However, it is preferable that the siloxane compound has anaverage molecular weight not less than 400 but not more than 50,000. Ifthe siloxane compound has an average molecular weight more than 50,000,the siloxane compound has excessively high viscosity, thus becomes apoor miscibility with the (A) soluble polyimide and the (B)(meth)acrylic compound. This leads to uneven dispersion of the siloxanecompound. Thus, in this case, a low flame resistance and/or a lowfilm-like forming property tend to occur. On the other hand, if thesiloxane compound has an average molecular weight less than 400, itbecomes difficult to obtain the siloxane compound, and further, there isa possibility that the siloxane compound has such a low viscosity thatcauses the siloxane compound to ooze out from the film. Further, a largeamount of the siloxane compound is necessary to attain the flameresistance effect.

[0318] The siloxane compound (1) may be a commercially availableproduct, but may be prepared in accordance with a generally usedproducing method. Specifically, dissolved into an organic solvent istriorganomonochlorosilane, diorgnaodichlorosilane,monoorganochlorosilane, tetrachlorosilane, or a partially hydrolyzedcondensation product thereof in an amount that is in accordance with amolecular weight of the siloxane compound and a ratio of M unit, D unit,T unit, and Q unit that constitute the siloxane compound. Then,triorganomonochlorosilane, diorgnaodichlorosilane,monoorganochlorosilane, tetrachlorosilane, or a partially hydrolyzedcondensation product thereof is reacted with an addition of water,thereby completing condensation polymerization. After that, the solventand the like are separated by distillation or the like. In this way, thesiloxane compound (1) is synthesized. By changing the amount of the rawmaterial, it is possible to produce a siloxane having an arbitrarymolecular weight and an arbitrary ratio of the units.

[0319] For example, by condensing, with an equilibrating catalyst and/ora condensing catalyst, the condensation product prepared by hydrolyzingonly an triorganomonochlorosilane and diorganodichlorosilane, it ispossible to obtain a siloxane compound having a straight-chain structurehaving no branch as indicated by the following formula (117):

[0320] (where R⁶⁰ is an organic group and a is an arbitrary integer).

[0321] Moreover, by arranging such that part of the raw materials are(i) the condensation product prepared by hydrolyzing at least one ofmonoorganotrichlorosilane and tetrachlorosilane, (ii) a hydrolysisproduct of diorganodichlorosilane, and (iii) the equilibrating catalystand/or the condensation catalyst, it is possible to obtain, via thecondensation reaction, a siloxane compound having a three dimensionalstructure (network structure) having a branch as indicated by thefollowing formula (118):

[0322] (where R⁶⁰ is an organic group).

[0323] Furthermore, the siloxane compound whose terminal group thefunctional group of at least one kind selected from the group consistingof vinyl group and (meth)acryl group is produced by an arrangement inwhich part of the raw material is triorganomonochlorosilane,diorgnaodichlorosilane, monoorganotrichlorosilane, or a partiallyhydrolyzed condensation product thereof which has a functional group ofat least one kind selected from the group consisting of vinyl group and(meth)acryl group.

[0324] The equilibrating catalyst and the condensation catalyst for usein the production of the silicone compound may be an acidic catalyst ofat least one kind selected from inorganic acids such as sulfuric acid,hydrochloric acid, and the like, and organic acids such as organicsulfonic acid, carboxylic acid. It is preferable that the equilibratingcatalyst and the condensation catalyst are sulfuric acid, hydrochloricacid, and organic sulfonic acid. It is more preferable that theequilibrating catalyst and the condensation catalyst are sulfuric acid.Based on a total amount of the raw-material organosilanes, an amount ofthe acidic catalyst to be added is in a range of from 0.5% by weight to10% by weight, preferably in a range of from 1% by weight to 7% byweight.

[0325] The addition of the catalysts is carried out preferably in two ormore stages, in order to avoid a production of a minute gel-likematerial as a by-product. Specifically, the acidic catalyst of a smallamount is added in the siloxane first. Then, the condensation is mainlyperformed with 1 to 5-hour stirring at a room temperature. A rest of theacidic catalyst is added therein, followed by 1 to 10-hour stirring at aroom temperature. In this case, the amount of the acidic catalyst to beadded first is generally in a range of 0.02% to 2% by weight, andpreferably in a range of 0.05% to 1% by weight, based on the totalamount of the raw-material organosilanes.

[0326] After the 1 to 10-hour stirring after the all of the acidiccatalyst is added, water is added therein. The addition of water is toconvert, into hydroxyl group, the sulfonic group bound with the terminalgroup of the siloxane. The conversion of the sulfonic group into thehydroxyl group results in further condensation.

[0327] An amount of water to be added is in a range of from 20 parts byweight to 60 parts by weight, and preferably in a range of from 30 partsby weight to 50 parts by weight, based on 100 parts by weight of theacidic catalyst. The reaction is hindered if the amount of the water istoo small or too large with respect to the acidic catalyst. Thus, it isdesirable that the amount of the water is within the range.

[0328] The condensation reaction is terminated by 0.5 to 3-hour stirringat a room temperature after the addition of water. After a waste acid isremoved, neutralizing dehydration of the acid catalyst remained. Anyneutralizer may be used, provided that the neutralizer is suitable forthis purpose. The neutralizer may be preferably sodium carbonate, sodiumhydroxide, sodium hydrogen carbonate, potassium carbonate, potassiumhydroxide and the like. Further, for better filtration and purificationfollowing this step, a dehydrating agent such as sodium sulfate or thelike may be added together with the neutralizer.

[0329] <Siloxane Compound (2)>

[0330] T/D type, T/D/Q type, D/Q type of combinations are examples ofcombinations including D unit for constituting the siloxane compound(2). In any of those combinations, it is necessary that D unit becontained in a range of 10 mol % to 95 mol %. It is preferable that Dunit is contained in a range of 20 mol % to 90 mol %. If D unit iscontained less than 10 mol %, the silicone resin has a poor flexibility,thereby failing to attain a sufficient flame resistance. Moreover, ifthe D unit is contained more than 95 mol %, the siloxane compound (2)has low dispersibility and solubility with respect to the solublepolyimide, whereby the photosensitive resin composition becomes poor inouter appearance, optical transmittance, and strength.

[0331] Therefore, in accordance with the good range of D unit content, Tunit content is in a range of 5 mol % to 90 mol %, in case of the T/Dtype.

[0332] Moreover, in case of T/D/Q type or D/Q type, the T unit contentis in a ragne of 0 to 89.99 mol %, preferably, 10 mol % to 79.99 mol %.Here, Q unit content is in a range of 0.01 mol % to 50 mol %. As long asa degree of freedom for space is secured, it is more advantageous tocontain more Q unit for reproducing the flame resistance, because Q unithas a high oxidation degree. However, if the siloxane compound (2)contains Q unit in more than 60 mol %, inorganic particle-like propertyof the siloxane compound (2) becomes too strong, whereby the siloxanecompound (2) has a poor dispersibility in the soluble polyimide.Therefore, it is necessary that the Q unit content be less than this.

[0333] Further, in consideration of a balance among the flameresistance, processability, and properties of products made therefrom,and from the D unit content and Q unit content, it is preferable that Tunit is contained in a range of from 10% by weight to 80% by weight,based on the total amount of the siloxane compound (2).

[0334] Examples of siloxane units preferably used as the siloxanecompound (2) are as follows: T unit may be preferably C₆H₅-Si_(3/2),CH₃-SiO_(3/2); D unit may be preferably (C₆H₅)₂—SiO_(2/2),CH₃—C₆H₅—SiO_(2/2), and (CH₃)₂—SiO_(2/2).

[0335] Of those preferably siloxane units, (CH₃)₂—SiO_(2/2) (dimethylsiloxane unit) is an example of D unit for giving the flexibility. Thedimethyl siloxane unit is most effective in giving the flexibility,whereas excessively large amount of the dimethyl siloxane unit gives lowflame resistance and makes it difficult to attain improvement in flameresistance. Therefore, it is not desirable that a large amount of thedimethyl siloxane unit is contained in the siloxane compound (2).Therefore, it is preferable that the dimethyl siloxane unit content inthe siloxane compound (2) is not more than 90 mol % based on a totalamount of D unit.

[0336] Moreover, of the preferable siloxane units, CH₃—C₆H₅—SiO_(2/2)(methyl siloxane unit) is most preferable, because the methyl siloxaneunit can give high phenyl group content as well as the flexibility.

[0337] Further, of the preferable siloxane units, (C₆H₅)₂-SiO_(2/2)(diphenyl siloxane unit) is excellent in maintaining the high phenylgroup content. However, the diphenyl siloxane unit has such a structurethat bulky phenyl groups are present in high density over Si. Therefore,a high the diphenyl siloxane unit content causes the siloxane compoundto have a molecular structure having a large steric hindrance, whereby asiloxane structure has a low degree of special freedom and the aromaticrings cannot overlap each other. The overlapping of the aromatic ringsis necessary for a flame resistance system to operate by coupling of thearomatic rings with each other. Thus, the arrangement in which a largeamount of the diphenyl siloxane unit is contained reduces the flameresistance.

[0338] Therefore, the siloxane compound (2) is so prepared that a rawmaterial containing these three units as D unit is added within therange. It is preferable that the raw material mainly containing themethyl phenyl siloxane unit is used.

[0339] Note that a weight average molecular amount of the siloxanecompound (2) is not particularly limited. However, it is preferable thatthe weight average molecular amount of the siloxane compound (2) is in arange of from 300 to 50,000. It is more preferable that the weightaverage molecular amount of the siloxane compound (2) is in a range offrom 400 to 30,000. If the weight average molecular amount of thesiloxane compound (2) is less than 300, there is a possibility that thesiloxane compound (2) oozes out in the B stage condition of thephotosensitive resin composition. Thus, the weight average molecularamount of the siloxane compound (2) less than 300 is not preferable. Onthe other hand, if the weight average molecular amount of the siloxanecompound (2) is more than 50,000, the siloxane compound (2) has a poorsolubility with respect to the developer, thereby resulting in a longdeveloping time and poor processability.

[0340] Examples of commercially available siloxane compounds that can beused in the present invention, and that have a high aromatic ringcontent are listed below.

[0341] For example: products of Shin-Etsu Silicones: KF50-100S, KF54,KF56, HIVAC F4, HIVAC F5, X-22-1824B, X-40-2134, X-40-2135, KR211,KR215, KR311, KR2621-1; products of GE Toshiba Silicones: XC99-B5664,and TSL9706; products of Toray Dow Corning Silicones Co., Ltd.: torefilE-601; and the like. But, the present invention is not particularlylimited to those. Of those, branched compounds are products of Shin-EtsuSilicones: KF56, KR211, KR215, KR311, KR2621-1, X-40-2134, X-40-2135;and the like. Those commercially available siloxane compounds may beused solely or in combination by mixing two or more of them together.

[0342] Note that, in case a siloxane compounds listed above is used asthe (D) fire retardant, it is well known that use of an inorganichydroxide in combination with the siloxane compound listed aboveimproves the flame resistance and self flame extinction property. In thepresent invention, therefore, the photosensitive resin composition orphotosensitive film may be so arranged that the siloxane compound isadded in combination with an inorganic hydroxide in case where thesiloxane compound is used as the (D) fire retardant.

[0343] However, the addition of the inorganic hydroxide gives adverseeffects on light transparency, surface smoothness, and electricinsulating property of the film. Therefore, it is preferable that anamount of the inorganic hydroxide to added in is not more than 10% byweight. Specific examples of inorganic hydroxide to be used are notparticularly limited. Thus, a well-known inorganic hydroxide may beused.

[0344] <(D) Fire Retardant Content (Amount of (D) Fire Retardant inComposition)>

[0345] Where the (D) fire retardant is not limited to a halogencompound, a phosphorous compound, and a siloxane compound, it ispreferable in general that the (D) fire retardant is used in a range offrom 10 parts by weight to 300 parts by weight, based on 100 parts byweight of the (A) soluble imide. If the amount of the (D) fire retardantis less than 10 parts by weight, the cured photosensitive film tends tohave a difficulty in having the flame resistance. If the amount of thefire retardant is more than 300 parts by weight, the curedphotosensitive film tends to have a poor mechanical property.

[0346] Moreover, where a total amount of the (A) soluble polyimide, (B)(meth)acrylic compound, and (D) fire retardant is based on, it ispreferable that the amount of the (D) fire retardant is used in a rangeof from 5% by weight to 50% by weight. If the amount of the (D) fireretardant is less than 5% by weight, the cured photosensitive film tendsto have a difficulty in having the flame resistance. If the amount ofthe (D) fire retardant is more than 50% by weight, the curedphotosensitive film tends to have a poor mechanical property.

[0347] Especially, where the total amount of the (A) soluble polyimide,(B) (meth)acrylic compound, and (D) fire retardant is put as 100 partsby weight, it is preferable in general that, regardless of the type ofthe (D) fire retardant, the (A) soluble polyimide is in a range of 30%by weight to 70% by weight, the (B) (meth)acrylic compound is in a rangeof 5% by weight to 50% by weight, and the (D) fire retardant is in arange of 1% by weight to 50% by weight. Of course, some types of the (D)fire retardant may have different preferable contents.

[0348] <Phosphorous Compound Content (Amount of Phosphorous Compound inComposition)>

[0349] Where the phosphorous compound is used as the (D) fire retardant,each type of the phosphorous compound has its own preferable content(amount to add in). Thus, the phosphorous compound is added in thepreferable amount as appropriate.

[0350] Firstly, in case where a phosphoric ester is used as aphosphorous compound (1), it is preferable that the phosphoric ester isin a range of from 3% by weight to 50% by weight based on the totalamount by weight. If the phosphoric ester is less than 3% by weight, thecured photosensitive film tends to have a difficulty in having the flameresistance. If the phosphoric ester is more than 50% by weight, thecured photosensitive film tends to have a mechanical property.

[0351] In case where a phosphorous compound (2) is used, it ispreferable that the phosphorous compound (2) is in a range of 5% byweight to 50% by weight. If the phosphorous compound (2) is less than 5%by weight, the cured photosensitive film tends to have a difficulty inhaving the flame resistance. If the phosphorous compound (2) is morethan 50% by weight, the cured photosensitive film tends to have a poormechanical property.

[0352] Moreover, improvement in the flame resistance and the likeimprovement can be attained by arranging such that an inorganic fillingmaterial, such as silica, talc, silicone, and the like is added incombination of the phosphorous compound (2). For these inorganic fillingmaterials, it is preferable that an amount of 0% by weight to 50% byweight is added based on the amount of the phosphorous compound (2).Further, for these inorganic filling materials, it is preferable that anamount of 0% by weight to 30% by weight is added with respect to thephosphorous compound (2). If the amount of the inorganic fillingmaterial is too large, the photosensitive cover lay film thus producedhas a poor light transparency and a poor shock resistance.

[0353] In case where a phosphazen compound among the phosphorouscompounds (2) is used in combination with the siloxane compound (1), itis preferable that an amount of the phosphazen compound to add in is ina ragne of 0% by weight to 200% by weight with respect to the siloxanecompound (1). Further, it is preferable that the amount of thephosphazen compound to add in is in a ragne of 0% by weight to 150% byweight with respect to the siloxane compound (1). If the amount of thephosphazen compound is too large, it becomes difficult to attain evendispersion of the phosphazen compound with the (A) soluble polyimide.Uneven dispersion of the phosphazen compound results in poor lighttransparency of the photosensitive film thus produced, and in poormechanical property and shock resistance of the cured photosensitivefilm.

[0354] Especially, where the phosphorous compound (2)(phosphorous-nitrogen compound) is contained as the (D) fire retardant,it is preferable that the (A) soluble polyimide is in a range of from30% by weight to 70% by weight, the (B) (meth)acrylic compound is in arange of from 1% by weight to 50% by weight, and thephosphorous-nitrogen compound is in a range of from 10% by weight to 50%by weight, based on 100% by weight of a total amount of the (A) solublepolyimide, (B) (meth)acrylic compound, and the phosphorous compound (2).

[0355] <Siloxane Compound Content>

[0356] Regardless of whether the siloxane compound (1) or the siloxanecompound (2) is used, siloxane compound content in the resin compositionin the present invention is specified as below, when the siloxanecompound is used as the (D) fire retardant. Note that the siloxanecompounds (1) and (2) may be used in combination.

[0357] To begin with, it is preferable that the siloxane compound iscontained in a range of from 1% by weight to 50% by weight, based on100% by weight of the total amount of the (A) soluble polyimide, (B)(meth)acrylic compound, and (D) fire retardant. It is more preferablethat the siloxane compound is contained in a range of from 5% by weightto 40% by weight, based on 100% by weight of the total amount. If theamount of the siloxane compound is less than 1% by weight, there is apossibility that the cured photosensitive cover lay film has aninsufficient flame hesitance effect. On the other hand, if the amount ofthe siloxane compound is more than 50% by weight, the following problemswould occur: the photosensitive resin composition is separated off;film-like formation property is deteriorated; and the film has aninferior outer appearance.

[0358] Moreover, in case where an imide(meth)acrylate compound iscontained as the (B) (meth)acrylic compound, the siloxane-based fireretardant is contained preferably in a range of 5% by weight to 50% byweight, more preferably in a range of 5% by weight to 40% by weight, andfurther preferably in a range of 10% by weight to 40% by weight, basedon a total amount of the (A) soluble polyimide and (B) (meth)acryliccompound. If the amount of the (D) fire retardant is less than 5% byweight, a cured cover lay film tends to have a difficulty in having theflame resistance. On the other hand, if the amount of the (D) fireretardant is more than 50% by weight, the cured cover lay film tends tohave a poor mechanical property.

[0359] Especially, in case where the siloxane compound having thebranched structure is contained as the (D) fire retardant, it ispreferable that the (A) soluble polyimide is contained in a range offrom 30% by weight to 70% by weight, the (B) (meth)acrylic compound iscontained in a range of from 1% by weight to 50% by weight, and thesiloxane having the branched structure is contained in a range of from10% by weight to 50% by weight, based on the 100% by weight of the (A)soluble polyimide, (B) (meth)acrylic compound, and the siloxane havingthe branched structure.

[0360] <Other Component>

[0361] The photosensitive resin composition and the photosensitive filmof the present invention may contains a component other than thecomponents (A) to (D). The other components is not particularly limitedin terms of type. For example, according to usage, various organicadditives, inorganic fillers, or various reinforcing agents may be addedtherein.

[0362] Especially, the photosensitive resin composition used in thepresent invention is preferably in a solution-form containing anappropriate organic solvent. If the photosensitive resin composition isdissolved in the appropriate organic solvent, the photosensitive resincomposition can be used in the solution (varnish) state, and used easilyduring production of the later-described photosensitive film, especiallyin applying and then drying.

[0363] The organic solvent for dissolving the photosensitive resincomposition in the present invention is not particularly limited,provided that each of the compositions (A) to (D) can be well dissolvedor dispersed in the organic solvent. However, an aprotic polar solventis preferable in consideration of solubility.

[0364] Specifically, the organic solvent may be, for example,N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N-benzyl-2-pyrrolidone,N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide,hexamethylphosphorictriamide, N-acetyl-ε-caprolactam,dimethylimidazolidinone, diethyleneglycoledimethylether,triethyleneglycoledimethylether, y-butyrolactone, dioxsane, dioxolane,tetrahydrofuran, chloroform, methylene chloride, or the like. Thoseorganic solvent may be used solely, or in combination so as to be usedas a mixture.

[0365] The organic solvent may be a solvent remained after used in thesynthetic reaction of the (A) soluble polyimide, or a solvent added tothe (A) soluble polyimide isolated. Moreover, in order to improve in aproperty for being able to be applied readily, an organic solvent suchas toluene, xylene, diethylketone, methoxybenzene, cyclopentanon, andthe like may be added in an amount in such a range that does notadversely affect the solubility of the polymer.

[0366] Moreover, by arranging such that2,2′-hexafluoropropylidenediphthalic dianhydride,2,3,3′,4′-biphenyltetracarboxylic dianhydride, or an ester acidanhydride mentioned above is used as a main component as the aciddianhydride, and an aromatic diamine having an amino group inm-position, a diamine having a sulfonic group, or a siloxanediamine isused as part of the diamine, a resultant (A) soluble polyimide has adramatically better solubility. Therefore, it is possible to dissolvethe resultant (A) soluble polyimide in a low-boiling point solventhaving a boiling point of 120° C. or less. The low-boiling point solventmay be: an ether-based solvent such as dioxsane, dioxolane,tetrahydrofuran, and the like; a halogen-based solvent such aschloroform, methylene chloride, and the like; and the like. Especially,for applying the photosensitive resin composition on the supporter anddrying the photosensitive resin composition thereon, the use of thelow-boiling point solvent having the boiling point of 120° C. or lessprevents thermal polymerization of the (B) (meth)acrylic compound to bemixed in. Thus, the use of the low-boiling point solvent having theboiling point of 120° C. is preferable.

[0367] <Photosensitive Film>

[0368] The thus obtained solution of photosensitive resin composition isdried to a film-like form, thereby obtaining a photosensitive film ofthe present invention. Here, the solution may be applied on a supportermade of a metal, a PET, or the like, and then dried and peeled off fromthe supporter, so as to be a single film. Alternatively, as describedlater, the photosensitive resin composition may be used as a laminate inwhich the film of the photosensitive resin composition is positioned ona supporting film (base film).

[0369] In other words, the photosensitive resin composition of thepresent invention may be in a solution (varnish) state, or may beprocessed into the photosensitive film. Moreover, as descried later, thephotosensitive film of the present invention may be a photosensitivelayer included in the laminate.

[0370] The usages of the photosensitive film are, for example: (1) as aresist film that acts as an etching resist for forming a copper circuiton a printed wiring board such as an FPC or the like, and is finallypeeled off after used as the etching resist; (2) as a photosensitivefilm that is formed on a circuit of a printed wiring board and holed ina predetermined position by, with a photo mask placed thereon, exposingto light and development the photosensitive film; (3) a protective filmfor insulating the circuit electrically; and the like usages.

[0371] Especially, the photosensitive film of the present invention canbe used not only for the usage (1), but also as the insulatingprotective film of the usage (3) by being thermally cured after used asthe photosensitive film of the usage (2). Note that the photosensitivefilm for the usage (1) is referred to as a photosensitive dry filmresist, and the photosensitive film for the usages (2) and (3) arereferred to as the photosensitive cover lay film. That is, thephotosensitive resin composition and the photosensitive film of thepresent invention may be used as the photosensitive cover lay film andthe photosensitive dry film resist.

[0372] <Production of Photosensitive Film>

[0373] Next, how to produce the photosensitive film is explained. Forproducing the photosensitive film of the present invention, firstly the(A) soluble polyimide, (B) (meth)acrylic compound, (C) photo reactioninitiator, and/or (D) fire retardant, and if necessary, the otheradditives, are dissolved evenly in an organic solvent.

[0374] The organic solvent used here may be any solvent that candissolve photosensitive resin composition therein. For Example, theorganic solvent may be: ether-based solvent such as dioxolane, dioxsane,tetrahydrofuran, and the like; ketone-based solvent such as acetone,methylethyleketone, and the like; alcohol-based solvent such asmethylalcohol, ethylealcohol, and the like; ad the like solvent. In casewhere the photosensitive resin composition is obtained in the solution(varnish) state, the solvent may not be added especially (see <OtherComponent>).

[0375] Those solvent may be used solely or a combination of two or moreof the solvents may be used. Because the solvent is removed in a laterstage, preferable is a solvent that can dissolve the (A) solublepolyimide, (B) (meth)acrylic compound, (C) photo reaction initiator, and(D) fire retardant, and, if possible, that has a lower boiling point.The use of such solvent is advantageous for facilitating the process.

[0376] Next, the photosensitive resin composition in the solution formis applied onto the supporting film evenly, and then dried by removingthe solvent off by using at least one of heating and blowing hot airthereon. Thereby the photosensitive film is obtained. In general, thephotosensitive film is so designed as a film in which the photosensitivecomposition is kept in a partially-cured state (B stage condition).Thus, in performing a thermopressing or thermo compression process, thephotosensitive film, which still a fluidity, is applied on the circuitof FPC so that the photosensitive film follows a rise-and-recess shapeof the circuit thereby making no gap between the photosensitive film andthe circuit. Curing of the photosensitive film is completed by (a)photo-cross linking reaction during exposure to the light, and (b)thermal curing due to heat applied in the pressing process and thermalcuring step performed after the pressing process.

[0377] <Drying Temperature>

[0378] A drying temperature in the removing the organic solvent anddrying for the production of the photosensitive film is preferably sucha temperature that does not cause, in (B) (meth)acrylic compound and thelike, reactions of acrylic group, epoxy group, and the other curinggroups such as double bonds and triple bonds. In general, the dryingtemperature is 180° C. or lower, preferably 150° C. or lower, morepreferably 120° C. or lower, and further preferably 100° C. or lower.

[0379] A drying time should be long enough to remove the organic solventoff. However, a shorter drying time is more advantageous forfacilitating the process. The drying time for drying the photosensitivefilm is not particularly limited. Specifically, for example, the dryingmay be carried out by (1) a method for drying the photosensitive film ina short time (about 2 to 3 minutes) at a temperature in a range of 80°C. to 120° C. or at 130° C.; (2) a method in which the drying is carriedout at a temperature gradually elevated from a low temperature, forexample, at a temperature programmed at 45° C. for 5 minutes, 65° C. forthe following 5 minutes, and then, 85° C. for the next 5 minutes.

[0380] Methods like the method (1), for drying the photosensitive filmin a short time at a relatively high temperature are suitable for a casewhere the photosensitive film has a thin thickness. The methods like themethod (1) has such advantages that a photosensitive film having a longlength can be produced with high productivity because the photosensitivefilm can be dried in such a short time.

[0381] However, in case where the photosensitive film has a thickness of50 μm or more, it takes a long time to evaporate off the solvent inwhich the photosensitive resin composition is dissolved. Thus, there isa possibility that the solvent remains in an inside of the film evenafter a surface of the film is dried by the high temperature. If thephotosensitive film that has been incompletely dried is used on the FPC,the photosensitive film causes such problems that the resin oozes outwhen the photosensitive film is formed on the FPC or the like, and thatbubbles are produced in the photosensitive film during thermal curingafter the photosensitive film is formed, subjected to pattern lightexposure, and developed. Therefore, if the thickness of thephotosensitive film is relatively thick, methods, like the method (2),for drying the photosensitive film at a gradually elevated temperatureis preferable, even though a longer drying time is necessary.

[0382] Moreover, if the photosensitive film is not sufficiently dried,the photosensitive film in the B stage condition becomes tacky (sticky).Further, in this case, there is a possibility that peeling of theprotective film layered on the photosensitive film causes a part of thephotosensitive film to be stuck and thus transferred on a surface of theprotective film. Furthermore, in this case, there is a possibility thatpeeling of the supporting film causes a part of the photosensitive filmto be stuck and thus transferred on a surface of the supporting film.

[0383] <Thickness of Photosensitive Film>

[0384] Moreover, there is no particular limitation in the thickness ofthe photosensitive film. For example, to be used as the cover lay film,a preferable thickness of the photosensitive film is in a range of 5 μmto 75 μm, a more preferable thickness is in a range of 10 μm to 60 μm,and a further preferable thickness is in a range of 10 μm to 40 μm. Onthe other hand, to be used as the dry film resist, a preferablethickness of the photosensitive film is in a range of 10 μm to 50 μm,and a more preferable thickness is in a range of 20 μm to 40 μm.

[0385] Regardless of whether the photosensitive film is used as thecover lay film or as the dry film resist, a photosensitive film having atoo thin thickness cannot fill the rise and recess shape formed by thecopper circuit and the base film of the FPC or the like. Moreover, thephotosensitive film having a too thin thickness cannot has a flat topsurface after being layered on the FPC, thereby resulting in a poorflexibility. Moreover, a photosensitive film having a too thickthickness tends to cause a difficulty in development a fine pattern,thereby resulting in low resolution and high possibility for curbing ofa cured sample.

[0386] <Laminate>

[0387] As described above, the photosensitive film of the presentinvention may be the photosensitive layer included in the laminate.Specifically, examples of the laminate of the present invention are: (1)an arrangement of a two-layer sheet in which the photosensitive layer ispositioned on the supporting film; (2) an arrangement of a three-layersheet in which a protective film is positioned on a photosensitive layerformed on the supporting film; and the like arrangement. Further, asdescribed later, the photosensitive layer is formed by, for example,drying a resin composition solution applied on the supporting film, theresin composition solution being prepared by dissolving thephotosensitive resin composition of the present invention in an organicsolvent.

[0388] <Supporting Film>

[0389] Materials of the supporting film may be, but not limited to,various generally commercially available films such as apolyethyleneterephthalate (PET) film, a polyphenylenesulfide (PPS) film,a polyimide film, and the like. Of those films, the PET film is mostpopular as the supporting film, because of it's relatively low price andcertain degree of heat resistance.

[0390] As to a contacting surface of the supporting film (a surface onwhich the photosensitive film is positioned, that is, on which thephotosensitive resin composition is applied), the contacting surface mayhave been subjected to a surface treatment in order to allow thephotosensitive film to more firmly stick to the supporting film with nogap, and to be more easily peeled off from the supporting film.

[0391] Moreover, a thickness of the supporting film is preferably notless than 5 μm but not more than 50 μm, and more preferably not lessthan 10 μm but not more than 30 μm. A supporting film having a too thinthickness tends to be easily wrinkled and poor in handling property.Moreover, in case of a supporting film having thick thickness, aphotosensitive dry film resist having a large length have an excessivelyheavy weight as a whole.

[0392] Furthermore, it is preferable to have the protective film on thephotosensitive cover lay film prepared by drying the photosensitiveresin composition applied on the supporting film. The protective filmprotects the photosensitive cover lay film from being attached with aforeign material in the air, and prevents quality deterioration of thephotosensitive cover lay film due to drying.

[0393] <Protective Film>

[0394] The present invention may be arranged as the three-layer sheet(laminate) in which the protective film is positioned on thephotosensitive film of the laminate (two-layer arrangement) of“supporting film/photosensitive film”. The protective film protects thephotosensitive cover lay film from being attached with a foreignmaterial in the air, and prevents quality deterioration of thephotosensitive cover lay film due to drying. It is preferable that theprotective film is laminated on a photosensitive film surface at atemperature in a range of 10° C. to 50° C., or a room temperature. Inthis way, the protective film is adhered on the photosensitive film withno gap therebetween. Thus, it is possible to protect the surface of thephotosensitive film. Note that an unnecessary high temperature appliedduring the formation of the protective film causes thermal expansion ofthe protective film thus produced. Such thermal expansion causes theprotective film to be wrinkled or curled after the formation.

[0395] Because the protective film is peeled off in using the laminate,it is preferable that the contact surface between the protective filmand the photosensitive film (the surface that is adhered on thephotosensitive film) has both (a) an appropriate firm stickiness duringstorage, and (b) a property for easy peeling-off.

[0396] Materials of the protective films may be, but not limited to: apolyethyleneterephthalate (PET) film, a polyphenylenesufide (PPS) film,a polyethylene film (PE film), a polyethylenevinylalcohol film (EVAfilm), “a copolymer film of polyethylene and ethyleviniylalcohol(hereinafter referred to as a (PE+PVA) copolymer film)”, “a laminate ofa PE film and (PE+EVA) copolymer film (hereinafter, PE-PE+EVA) laminatefilm)”, or “a film prepared by coextrusion of (PE+EVA) polymer andpolyethylene (that is, a film having a PE film surface on one side, anda (PE+EVA) copolymer film on the other side (hereinafter, a PE+PE+EVAcoextrusion film))”. The PE film is advantageous in its low cost andexcellent surface smoothness. Moreover, the (PE+EVA) copolymer film hasboth (a) an appropriate firm stickiness during storage, and (b) aproperty for easy peeling-off.

[0397] In case the PE-PE+EVA laminate film or the PE-PE+EVA coextrusionfilm is used as the protective film, an arrangement is preferable that a(PE+EVA) copolymer film surface is the contact surface to be in contactwith the photosensitive film, and a PE film surface is in contact withthe supporting film.

[0398] The use of the protective film gives such an advantage that a topsurface of the three-layer sheet (laminate) including the protectivefilm, the photosensitive film, and the supporting film, has a goodsurface smoothness when the three-layer sheet is rolled up.

[0399] Moreover, the protective film may have a light shieldingproperty. To give the light shielding property, the PE film is coloredin a color that shuts off light in a wavelength range that a lightinitiation reacting agent and a sensitizer coloring agent contained inthe photosensitive film absorb. The use of the colored protective filmmakes it easier to distinguish the supporting film and the protectivefilm in the photosensitive cover lay film thus three-layered. Thus, itbecomes easier to peel off the protective film.

[0400] <Storage>

[0401] In case of storing the two-layer sheet that has not be providedwith the protective film thereon, the photosensitive film of the presentinvention may be stored in a rolled-up form so that a surface of thephotosensitive film will not be dried or be in contact with oxygen.Moreover, in case of storing the three-layer sheet that is provided withthe protective film, the photosensitive film of the present inventionmay be stored in a rolled-up form or as a pile of sheets that is cut inan appropriate size and piled up.

[0402] For the photosensitive film, to store as the three-layer sheet byproviding the protective film is more preferable than to store as thetwo-layer sheet, because a long-time contact of the photosensitive filmwith the air allows a foreign material to adhere on the photosensitivefilm more easily, and causes a dramatic reduction in storage stabilityof the photosensitive film by oxygen and moisture in the air.

[0403] <Production of FPC>

[0404] The following explains an example of the usage of thephotosensitive dry film resist thus obtained.

[0405] Usually, the production of the FPC is so productive because afilm having a long length is processed continuously by applying anadhesive, drying, and applying a copper foil. However, it isalmost-manual process to (i) open a hole or window in that area of thephotosensitive cover lay film which is to be positioned above a terminalsection of the circuit or a jointing section of the circuit (a jointingsection to be used to join with parts), and (ii) to position the hole orthe like of the cover lay film to the terminal section of the circuit orthe jointing section of the circuit. Further, the opening of the hole orthe like, and the positioning are carried out with a small work size,and the cover lay film is bonded with the circuit batchwize. Therefore,the opening of the hole or the like and the positioning is poor inworkability, positional accuracy, and cost.

[0406] To the contrary, the photosensitive film or the laminate of thepresent invention can be placed on the printed substrate directlywithout using an adhesive agent. Further, the hole for allowing thejointing with an FPC terminal section can be opened by light exposureand development after the photosensitive film is bonded with the FPC. Asa result, it is possible to solve the problem in the positional accuracyand workability during the FPC production.

[0407] Specifically, for example, in case where the FPC is produced byusing the photosensitive film made of the three-layer sheet as thelaminate of the present invention, the photosensitive film is bondedwith a copper-clad laminate (copper-clad laminate attached with acircuit, a circuit-attached CCL) by thermo compression (for example,heat laminating, pressing).

[0408] <Bonding of Film and FPC>

[0409] A compression-bondable temperature refers to a lowest temperaturethat enables thermo compression. Thermo compression possible temperatureis a temperature necessary for compression bonding of the photosensitivefilm of the present invention and a target object onto which thephotosensitive film is to be bonded. The temperature range differsdepending on from which type of raw materials the film is made. Thecompression-bondable temperature is measured by measuring a lowesttemperature that allows the photosensitive cover lay film to becompression-bonded on a polyimide film and a glossy surface of a copperfoil by thermal lamination of the photosensitive film in the B stagecondition. The polyimide film used here is an NPI film made by KanekaCorp. and has a thickness of 25 μm. The copper foil is an electrolyticcopper foil made by Mitsui Mining & Smelting Co., Ltd. and has athickness of 38 μm.

[0410] Whether the compression bonding is successful or not is checkedby trying to peel off the photosensitive cover lay film from thepolyimide film and the glossy surface of the copper foil after thermallamination. If the photosensitive cover lay film cannot be peeled off,the compression bonding is judged as successful. Thecompression-bondable temperature is a temperature not more than 150° C.,preferably in a range of from 20° C. to 150° C., and more preferably ina range of from 50° C. to 150° C. A lower compression-bondabletemperature is preferable. It is preferable that thecompression-bondable temperature is not more than 130° C. It is furtherpreferable that the compression-bondable temperature is not more than110° C.

[0411] A photosensitive film having a compression-bondable temperatureout of the range likely have a problem when used. Specifically, for aphotosensitive film that cannot be compression-bonded without a highertemperature than this range, there is a possibility that warping orcurling occurs in the photosensitive film after cooling due to a thermalexpansion coefficient difference between the photosensitive dry film anda member to which the photosensitive dry film is adhered, because, forexample, heat initiates the reaction that supposes to be caused by lightirradiation, and a difference between a compression temperature and anormal temperature is too large. Moreover, for a photosensitive filmthat cannot be compression-bonded without a lower temperature than thisrange, it is necessary to cool down the photosensitive film. There is apossibility that the cooling result in dew condensation on a surface dueto temperature differences in the steps, thereby deteriorating thephotosensitive dry film in property due to water produced from the dewcondensation.

[0412] Here, the copper foil has the surface (glossy surface) that isglossy, and a surface (rough surface) that is not glossy. Thermocompression to the rough surface is easier than thermo compression tothe glossy surface, because the rough surface has a larger surface area.Thus, it is possible to perform thermo compression of the photosensitivecover lay film to the rough surface of the copper foil at a temperatureat which the photosensitive cover lay film can be thermo-compressed ontothe glossy surface of the copper foil.

[0413] If a temperature in the layering is excessively high, aphotosensitive reactive parts are cross-linked thereby causing the filmto cure. This causes the film to lose its function as the photosensitivecover lay film. Thus, it is preferable to carry out the layering at alow temperature. Specifically, the temperature is in a range of from 20°C. to 150° C., in a range of from 60° C. to 150° C., further preferablyin a range of from 60° C. to 120° C., more preferably in a range of from80° C. to 120° C. If the temperature is too low, the photosensitive filmhas a poor fluidity. The poor fluidity makes it difficult to cover afine circuit on a flexible printed wiring board, and tends to result inpoor firm stickiness.

[0414] In this way, the laminate layered as “a circuit-attachedCCL/photosensitive film/supporting film” in this order is prepared. Thesupporting film may be peeled off after completion of the lamination, ormay be peeled off after completion of the exposure. For a sake ofprotection of the photosensitive cover lay film, to peel off thesupporting film after the exposure with the photomask applied thereon ispreferred.

[0415] Moreover, after adhered on the circuit on the flexible printedwiring board, light (such as ultraviolet light) is irradiated thereon.Then, the photosensitive film is thermally cured to a cover lay forprotecting and insulating the circuit.

[0416] <Light-Exposure/Development>

[0417] Here explains how the light-exposure/development are performed. Aphotomask is applied on the supporting film of the laminate layered as“a circuit-attached CCL/photosensitive film/supporting film”. Then, thelaminate exposed to the light. After that, the supporting film is peeledoff. Then, the laminate is developed. By doing this, unexposed part isdissolved and removed, thereby forming a hole or the like in a desiredposition, and fabricating the film into a desired shape. The developmentmay be performed with a generally-used positive type photo resistdeveloping apparatus.

[0418] Because the photo reaction initiator contained in thephotosensitive cover lay film generally absorbs light of wavelengths of450 nm or lower, a light source used for the exposure need effectivelyemit light of wavelength in a range of from 300 nm to 430 nm.

[0419] <Developer>

[0420] Moreover, the developer may be a basic aqueous solution or anorganic solvent. As a solvent to dissolve a basic compound, water or anorganic solvent may be used. For better solubility of the polyimide, awater-soluble organic solvent may be further added, such as methanol,ethanol, propanol, isopropylalcohol, isobutanol, N-methyl-2-pyrrolidone,N,N-dimethylformamide, N,N-dimethylacetamide, or the like. A combinationof those water-soluble organic solvents may be used. Consideringenvironmental influence, it is preferable not to use the organicsolvent, and it is most preferable to use an alkali aqueous solution asthe developer.

[0421] Examples of the basic compound are alkali metals, alkali earthmetals, hydroxides of ammonium ion, carbonates of ammonium ion, andamine compounds.

[0422] Specifically, examples of the basic compound are: amine compoundssuch as 2-dimethylaminoethanol, 3-dimethylamino-1-propanol,4-dimethylamino-1-butanol, 5-dimethylamino-1-pentanol,6-dimethylamino-1-hexanol, 2-dimethylamino-2-methyl-1-propanol,3-dimethylamino-2,2-dimethyl-1-propanol, 2-diethylamino ethanol,3-diethylamino-1-propanol, 2-diisopropylaminoethanol,2-di-n-butylaminoethanol, N,N-dibenzyl-2-aminoethanol,2-(2-dimethylaminoethoxy) ethano, 2-(2-diethylaminoethoxyl) ethanol,1-dimethyamino-2-propanol, 1-diethylamino-2-propanol,N-methyldiethanolamine, N-ethyldiethanolamine, N-n-butyldiethanolamine,N-t-butyldiethanolamine, N-lauryldiethanolamine,3-diethylamino-1,2-propandiol, triethanolamine, triisopropanolamine,N-methylethanolamine, N-ethylethanolamine, N-n-butylethanolamine,N-t-butylethanolamine, diethanolamine, diisopropanolamine,2-aminoethanol, 3-amino-1-propanol, 4-amino-1-butanol,6-amino-1-hexanol, 1-amino-2-propanol, 2-amino-2,2-dimethyl-1-propanol,1-aminobutanol, 2-amino-1-butanol, N-(2-aminoethyl)ethanoamine,2-amino-2-methyl,1,3-propandiol, 2-amino-2-ethyl-1,3-propandiol,3-amino-1,2-propandiol, 2-amino-2-hydroxymethyl-1,3-propandiol,tetramethyammoniumhydroxide, tetraethyammoniumhydroxide,tetrapropylammoniumhydroxide, tetraisopropylammoniumhydroxide,aminomethanol, 2-aminoethanol, 3-aminopropanol, 2-aminopropanol,methylamine, ethylamine, propylamine, isopropylamine, dimethylamine,diethylamine, dipropylamine, diisopropylamine, trimethylamine,triethylamine, tripropylamine, triisopropylamine, and the like; sodiumhydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate,potassium carbonate, ammonium carbonate, sodium hydrogen carbonate,potassium hydrogen carbonate, ammonium hydrogen carbonate; hydroxides orcarbonate of alkali metals, alkali earth metals or ammonium ion; and thelike. Those compounds may be used solely or as a combination of two ormore of them. Further, compounds other than those compounds may be used,provided that the compounds is soluble in water or alcohol, and asolution thereof is alkali.

[0423] Concentration of the basic compound is in a range of from 0.1% to50% by weight. In consideration of effects on the supporting substratesand the like, the concentration of the basic compound is preferably in arange of 0.1% to 30% by weight, more preferably in a range of 0.1% to10% by weight. In consideration of effects on the film, it is furtherpreferable that the concentration is in a range of 0.1% to 5% by weight.

[0424] The pattern thus formed by the development is then washed with arinsing liquid so as to remove a developing solvent. Preferable examplesof the rinsing liquid are methanol, ethanol, isopropylalcohol, water andthe like, which have a good miscibility with the developer.

[0425] That is, it is necessary for the photosensitive film of thepresent invention to be developable with the alkali aqueous solutionafter being exposed to light. Moreover, it is preferable that the alkaliaqueous solution used as the developer contains at least one of acarbonate of an alkali metal, a hydroxide of an alkali metal, and atetraammonium hydroxide.

[0426] The photosensitive cover lay film thus developed becomes aninsulating protective film for a circuit after being cured by thermalcuring. Thereby, a flexible printed wiring board is prepared.

[0427] <Properties of Photosensitive Film>

[0428] The photosensitive film of the present invention (thephotosensitive resin composition formed in a film-like form), which areused as such, is of high quality by satisfying at least one of thoseproperties (1) to (5):

[0429] (1) having a curing temperature of 200° C. or less;

[0430] (2) having a post-curing thermolysis starting temperature of 300°C. or more;

[0431] (3) having a line-to-line insulating resistance of 10¹³ Ω or moreafter 24-hour moisture conditioning at 20° C. and 65% RH;

[0432] (4) being capable of sustaining a resistance of 10¹⁰ Ω or morefor a period of 500 hours or longer at application of a direct currentof 100V at 85° C. at 85% RH, in case where the photosensitive film isapplied on a cupper-clad board on which a comb-shaped pattern havingline/space=100 μm/100 μm is formed; and

[0433] (5) having a soldering heat resistance of 300° C. or more after48-hour humidity control at 35° C. at 85% RH.

[0434] By satisfying the properties (1) to (5), the photosensitive filmof the present invention become suitable for use in the FPCs, heads ofhard disc apparatuses, and various electronic parts.

[0435] Especially, the soldering heat resistance of (5) will bedescribed here. For example, in the FPCs, soldering is carried out byexposing the photosensitive film to a high temperature of 200° C. ormore for a few seconds. Thus, the photosensitive film having a highersoldering heat resistance after curing is preferable. When measuredsolely after curing, the photosensitive film of the present inventionhas, a thermolysis temperature of 300° C. or more, more preferably 320°C. or more, and further preferably 340° C. or more.

[0436] Note that a conductive layer of the FPCs is made of copper inmany cases. By exposing copper to a temperature above 200° C., acrystalline structure of copper is changed, thereby resulting in a lowstrength of a circuit made of copper. Therefore, it is very preferablethat the curing temperature is 200° C. or less.

[0437] Moreover, it is preferable that the photosensitive film of thepresent invention is capable of being compression-bonded at 150° C. orless to a target object to which the photosensitive film is to belaminated. Further, in case where the target object to which thephotosensitive film is to be laminated is a polyimide film or a copperfoil having a glossy surface, it is preferable that acompression-bondable temperature in the B stage condition is in a rageof 20° C. to 150° C.

[0438] Moreover, in the photosensitive film of the present invention, adesired pattern is formed by the exposure and development, as describedabove. Here, the development process is performed by showering thedeveloper so as to dissolve unexposed part. Thus, if the photosensitivefilm has a low adhesiveness, there is a possibility that thephotosensitive film falls off during the development process. Therefore,it is preferable that the photosensitive film (photosensitive resincomposition) of the present invention has an adhesion strength of 5 Pa·mor more. It is more preferable that the photosensitive film(photosensitive resin composition) of the present invention has anadhesion strength of 10 Pa·m or more.

EXAMPLES

[0439] In the following, the present invention is describedspecifically, with reference to examples and comparative examples towhich the present invention is not limited. Note that, unless otherwisespecified, names of products following names of manufacturer are productnames or product number in the examples and comparative examples.

[0440] [Evaluation of Properties]

[0441] Properties of the photosensitive film and laminate were evaluatedin the following manner in examples 1 to 4 and comparative example 1.

[0442] Thermolysis starting temperature was determined by measuring atemperature range from a room temperature to 500° C. at a programmingrate of 10° C./min in air by using TG/DTA220 made by Seiko Corporation.A temperature at which weight was reduced by 5% was determined asthermolysis starting temperature.

[0443] Degree of elasticity was measured following JIS C 2318.

[0444] Peel adhesion strength was measured following JIS C 6481:Peel-back strength (90°). Note that the measurement of the peel adhesivestrength was carried out with a width of 3 mm, and measurement resultswere converted to be based on a width of lcm.

[0445] The weight average molecular weight was measured under thefollowing conditions by using GPC of Waters Corp.: Column: two columns(KD-806M made by Shodex Corp.); Temperature 60° C.; Detector: R₁; FlowRate: 1 ml/min; Carrier Liquid: DMF (lithium bromide 0.03M, phosphoricacid 0.03M); Sample Concentration: 0.2% by weight; Injection Amount: 20μl; Reference substance: polyethyleneoxide.

Example 1

[0446] Into a separable flask of 2,000 ml provided with a stirringapparatus, 4.30 g (0.01 mol) of bis[4-(3-aminophenoxy)phenyl]sulfone(BAPS-M), 24.9 g (0.03 mol) of KF-8010 (R²²=—CH₂CH₂CH₂—, a=10, R²³=CH₃in Formula (108)) available from Shin-Eetsu chemical Co., Ltd. assiloxanediamine (siliconediamine), and 200 g of N,N-dimethylformamide(DMF) were poured. Then, 29.4 g (0.10 mol) of2,3,3′,4′-biphenyltetracarboxylic dianhydride (a-BPDA) was quickly addedtherein with severe stirring. The stirring was continued for another 30minutes thereafter. Thereby, a solution was prepared.

[0447] Next, a solution of 17.2 g (0.06 mol) ofbis(4-amino-3-carboxy-phenyl)methane in 75 g of DMF was added in thesolution thus prepared, followed by 4-hour stirring. Thereby a polyamicacid solution was obtained. The polyamic acid solution had a weightaverage molecular weight (Mw) of 60,000.

[0448] The polyamic acid solution was transferred into a vat coated witha fluorine-based resin. The polyamic acid in the vat was heated in avacuum oven under a reduced pressure of 5 mmHg at a temperate programmedas follows: 150° C. for 10 minutes, 160° C. for 10 minutes, 170° C. for10 minutes, 180° C. for 10 minutes, 190° C. for 10 minutes, and then210° C. for 30 minutes.

[0449] Then, the vat was taken out of the vacuum oven, thereby obtaininga silicone polyimide as (A) soluble polyimide containing carboxylic acidof 71.5 g. The silicone polyimide had an Mw of 62,000 (COOH equivalent:602).

[0450] A solution was prepared by adding, into 25 g of the siliconepolyimide and 150 g of dioxolane, (a) photo reaction initiators (0.5 g(1.2 mmol) of bis(2,4,6-trimethylbenzoil)-phenylphosphineoxide, 25 g ofABE-30 (bisphenol A EO modified (n=30) diacrylate; made by Shin-NakamuraChemical Co., Ltd.), and 1.5 g of epoxy 828 (made by Yuka Shell Corp.)),and (b) a polymerization inhibitor (10 mg of methoxy phenol). Thesolution was applied on a PET film having a thickness of 25 μm. Then,the solution applied on the PET film was dried at 45° C. for 5 minutesand then at 65° C. for 5 minutes.

[0451] In this way, a two-layer sheet (laminate) was obtained, which wasstructured as photosensitive film (38 μm in thickness)/PET (25 μm inthickness).

[0452] Laminating process was carried out by applying a temperature of100° C. and a force of 100N/cm on the two-layer sheet placed on a copperfoil (made by Mitsui Mining & Smelting Co., Ltd., 3EC-VLP 1 ounce) sothat the photosensitive film and the PET film were laminated in thisorder. The laminating process was following by light exposure performedby a light-exposing machine (available from Nippon Uthograph Inc.;Table-top printer 26-1KS) (Light Exposure Condition: light of 400 nm wasapplied by 300 mJ/cm²).

[0453] Then, a flexible copper-clad laminate was obtained by, after thelight exposure, peeling off the PET film and then curing at 180° C. for2 hours. Note that the flexible copper-clad laminate had a two-layerstructure of copper film/photosensitive film, and had not provided witha copper circuit thereon.

[0454] A peel adhesion strength of the flexible copper-clad laminate wasmeasured following JIS C 6481 (peel-back strength (180°). It was foundthat the peel adhesion strength of the flexible copper-clad laminate was11.8N/cm (1.2 kg weight/cm). Moreover, it was observed that 1-minuteimmersion of the flexible copper-clad laminate in a solder bath at 260°C. gave no defect such as swelling and the like to the flexiblecopper-clad laminate.

[0455] Moreover, the copper foil was removed from the flexiblecopper-clad laminate by etching, thereby obtaining a curedphotosensitive film (cover lay film). It was found that the cover layfilm had a degree of elasticity of 1,000N/mm², extension of 25%, and athormolysis starting temperature of 370° C.

[0456] A lamination was prepared by laminating a photosensitive film(sunfort made by Asahi Kasei Corp.) on the copper foil of the flexiblecopper-clad laminate. The lamination was exposed to light via aphotomask of a pattern (comb-shaped pattern) in which ten lines ofline/space=100/100 μm as shown in FIG. 1 were arranged in a comb-shape,and then developed, thereby etching the copper foil. After that, thephotosensitive film (sunfort mentioned above) was peeled off. In thisway, a comb-shape-patterned circuit made from the copper foil wasprepared as shown in FIG. 1 (see FIG. 1 for sizes).

[0457] Further, the two-layer sheet was placed on the patterned circuitso as to cover the patterned circuit so that the photosensitive film andthe PET film were laminated in this order. Then, laminating process ofthe two-layer sheet on the patterned circuit was carried out by applyinga temperature of 100° C. and a force of 100N/cm. The laminating processwas followed by light exposure performed by a light-exposing machine(available from Nippon Uthograph Inc.; Table-top printer 26-1KS) (LightExposure Condition: light of 400 nm was applied by 300 mJ/cm²). Then, anFPC having a lamination structure of photosensitive film/copperfoil/photosensitive film was obtained after peeling off the PET film andthen curing at 180° C. for 2 hours after the light exposure.

[0458] A resistance (insulating resistance) of the FPC was measuredafter 1-minute application of a DC of 500V on the FPC, which had beensubjected to moisture conditioning carried out under the followingconditions:

[0459] (1) Normal Condition: after moistening at 20° C. in 65% RH for 24hrs: =9×10¹⁵ Ω.

[0460] (2) Moisture Condition: after moistening at 35° C. in 85% RH for24 hrs: =3×10¹⁵ Ω.

[0461] Moreover, the two-layer sheet was placed on a copper foil so thatthe photosensitive film and the PET film were laminated in this order.Then, laminating process of the two-layer sheet placed on the copperfoil was carried out by applying a temperature of 100° C. and a force of100N/cm. After the laminating process, a photo mask having a pattern ofline/space=100/100 μm was placed thereon. The two-layer sheet placed onthe copper foil was exposed to light with the photo mask placed thereon(Light Exposure Condition: light of 400 nm was applied by 300 mJ/cm²).After that, the PET film was peeled off therefrom. Then, thephotosensitive film on the copper foil was developed with 1% KOH aqueoussolution (at a liquid temperature of 40° C.). The photosensitive film onthe copper foil was then cured at 180° C. for 2 hours. The patternformed on the photosensitive film thus prepared was observed under amicroscope. The microscopic observation showed that the pattern ofline/space=100/100 μm was formed thereon.

Example 2

[0462] Into a separable flask of 2,000 ml provided with a stirringapparatus, 5.84 g (0.02 mol) of 1,3-bis[3-aminophenoxy]benzene (APB)(made by Mitsui Chemicals Corp.) as an aromatic diamine, 16.6 g (0.02mol) of KF-8010 available from Shin-Etsu Chemical Co., Ltd. assiloxanediamine, and 200 g of DMF were poured. Then, 15.5 g (0.05 mol)of 3,3′,4,4′-biphenylethertetracarboxylic dianhydride (ODPA) was quicklyadded therein with severe stirring. The stirring was continued foranother 30 minutes thereafter.

[0463] Next, 8.4 g (0.05 mol) of 4,6-diaminoresorcinol was added into asolution thus prepared. Then, the solution was stirred for 30 minutes.After the stirring, 2,2-bis(4-hydroxyphenyl)propanedibenzoate-3,3′,4,4′-tetra carboxylic dianhydride (ESDA) of 28.8g (0.05 mol) was added to the solution. Then, the solution was stirredfor 2 hours. Thereby, a polyamic acid solution was obtained, which hadan Mw of 70,000.

[0464] The polyamic acid solution was transferred into a vat coated witha fluorine-based resin. The polyamic acid in the vat was heated in avacuum oven under a reduced pressure of 5 mmHg at a temperate programmedas follows: 150° C. for 10 minutes, 160° C. for 10 minutes, 170° C. for10 minutes, 180° C. for 10 minutes, 190° C. for 10 minutes, and then210° C. for 30 minutes.

[0465] Then, the vat was taken out of the vacuum oven, thereby obtaininga soluble polyimide containing water-product group of 70.0 g. Thesilicone polyimide had an Mw of 69,000 (OH equivalent: 665).

[0466] A solution was prepared by mixing 25 g of silicone polyimide, 0.5g (1.2 mmol) of bis(2,4,6-trimethylbenzoil)-phenylphosphineoxide, 5 g ofallonix M-208 (bisphenol F EO modified (n=2) diacrylate (available fromToagosei Co., Ltd.), 20 g of ABE-30 (made by Shin-Nakamura Chemical Co.,Ltd.) (bisphenol A EO modified (n=30) diacrylate), 1.5 g of epoxy 828(made by Yuka Shell Corp.), and an polymerization inhibitor (10 mg ofmethoxyphenol). The solution was applied on a PET film having athickness of 25 μm. Then, the solution applied on the PET film was driedat 45° C. for 5 minutes. After that, the PET film was peeled offtherefrom, thereby leaving a film. The film was pinned on a pin frameand then dried at 65° C. for 5 minutes.

[0467] In this way, a two-layer sheet (laminate) was obtained, which wasstructured as photosensitive film (38 μm in thickness)/PET (25 μm inthickness).

[0468] Then, a flexible copper-clad laminate was obtained by peeling offthe PET film and then curing at 180° C. for 2 hours. Note that theflexible copper-clad laminate had a two-layer structure of copperfilm/photosensitive film, and had not provided with a copper circuitthereon.

[0469] It was found that a adhesion strength of the flexible copper-cladlaminate was 10.8 N/cm (1.1 kg weight/cm). Moreover, it was observedthat 1-minute immersion of the flexible copper-clad laminate in a solderbath at 260° C. gave no defect such as swelling and the like to theflexible copper-clad laminate.

[0470] Moreover, the copper foil was removed from the flexiblecopper-clad laminate by etching, thereby obtaining a curedphotosensitive film (cover lay film). It was found that the cover layfilm had a degree of elasticity of 1,500N/mm², extension of 15%, and athormolysis starting temperature of 375° C.

[0471] Furthermore, an FPC was prepared as in Example 1. Then, aninsulating resistance of the FPC was measured, the FPC having beensubjected to 24-hour moisture conditioning carried out under thefollowing conditions:

[0472] (1) Normal Condition: after moistening at 20° C. in 65% RH for 24hrs: =8×10¹⁵ Ω.

[0473] (2) Moisture Condition: after moistening at 35° C. in 85% RH for24 hrs: =3×10¹⁵ Ω.

[0474] Moreover, the two-layer sheet was placed on a copper foil so thatthe photosensitive film and the PET film were laminated in this order.Then, laminating process of the two-layer sheet placed on the copperfoil was carried out by applying a temperature of 100° C. and a force of100N/cm. After the laminating process, a photo mask having a pattern ofline/space=100/100 μm was placed thereon. The two-layer sheet placed onthe copper foil was exposed to light with the photo mask placed thereon(Light Exposure Condition: light of 400 nm was applied by 300 mJ/cm²).After that, the PET film was peeled off therefrom. Then, thephotosensitive film on the copper foil was developed with 1% KOH aqueoussolution (at a liquid temperature of 40° C.). The photosensitive film onthe copper foil was then cured at 180° C. for 2 hours. The patternformed on the photosensitive film thus prepared was observed under amicroscope. The microscopic observation showed that the pattern ofline/space=100/100 μm was formed thereon.

Example 3

[0475] Into a separable flask of 2,000 ml provided with a stirringapparatus, 8.61 g (0.02 mol) of BAPS-M, and 260 g of DMF were poured in.Then, 57.65 g (0.1 mol) of ESDA was added quickly therein with a severstirring. The stirring was continued for another 30 minutes thereafter.Then, 24.9 g (0.03 mol) of KF-8010 (made by Shin-Etsu Silicone) wasadded therein as a siloxanediamine. 30 minute stirring followed thisaddition of KF-8010. Then, 9.81 g (0.05 mol) of 2,5-diaminoterephthalicacid polyamic acid solution was obtained. The polyamic acid had an Mw of53,000. Here, reaction was carried out under cooling with ice water.

[0476] The polyamic acid solution was transferred into a vat coated witha fluorine-based resin. The polyamic acid in the vat was heated in avacuum oven under a reduced pressure of 5 mmHg at a temperate programmedas follows: 150° C. for 10 minutes, 160° C. for 10 minutes, 170° C. for10 minutes, 180° C. for 10 minutes, 190° C. for 10 minutes, and then210° C. for 30 minutes.

[0477] Then, the vat was taken out of the vacuum oven, thereby obtaining105 g of a thermoplastic polyimide (silicone polyimide) having acarboxyl group. The polyimide had an Mw of 50,000 (COOH equivalent:973).

[0478] Into 25 g of the silicone polyimide thus prepared, 0.3 g of4,4′-bis(diethylamino)benzophenone, 1.0 g of BTTB (25% toluene solution;made by NOF Corp.), 20 g of ABE-30 (made by Shin-Nakamura Chemical Co.,Ltd.) (bisphenol A EO modified (n=30) diacrylate), 5 g of ABE-10 (madeby Shin-Nakamura Chemical Co., Ltd.) (bisphenol A EO modified (n=10)diacrylate), and an polymerization inhibitor (10 mg of methoxyphenol)were added. Thereby, a photosensitive resin composition in a solution(varnish) was prepared.

[0479] The photosensitive resin composition was applied on a PET filmhaving a 251 μm thickness, and then dried at 45° C. for 5 minutes. Then,the PET film was peeled off therefrom, thereby leaving a film. The filmwas pinned on a pin frame and then dried at 65° C. for 5 minutes. Inthis way, a two-layer sheet (laminate) was obtained, which wasstructured as photosensitive film (60 μm in thickness)/PET (25 μm inthickness).

[0480] Then, a flexible copper-clad laminate was obtained by peeling offthe PET film and then curing at 180° C. for 2 hours. Note that theflexible copper-clad laminate had a two-layer structure of copperfilm/photosensitive film, and had not provided with a copper circuitthereon.

[0481] It was found that a adhesion strength of the flexible copper-cladlaminate was 10.0 N/cm (1.02 kg weight/cm). Moreover, it was observedthat 1-minute immersion of the flexible copper-clad laminate in a solderbath at 260° C. gave no defect such as swelling and the like to theflexible copper-clad laminate.

[0482] Moreover, the copper foil was removed from the flexiblecopper-clad laminate by etching, thereby obtaining a curedphotosensitive film (cover lay film). It was found that the cover layfilm had a degree of elasticity of 1,250N/mm², extension of 25%, and athormolysis starting temperature of 380° C.

[0483] Furthermore, an FPC was prepared in the same manner as inExample 1. Then an insulating resistance of the FPC was measured, theFPC having been subjected to 24-hour moisture conditioning carried outunder the following conditions:

[0484] (1) Normal Condition: after moistening at 20° C. in 65% RH for 24hrs: =7×10¹⁵ Ω.

[0485] (2) Moisture Condition: after moistening at 35° C. in 85% RH for24 hrs: =1×10¹⁵ Ω.

[0486] Moreover, the two-layer sheet was placed on a copper foil so thatthe photosensitive film and the PET film were laminated in this order.Then, laminating process of the two-layer sheet placed on the copperfoil was carried out by applying a temperature of 100° C. and a force of100N/cm. After the laminating process, a photo mask having a pattern ofline/space=100/100 μm was placed thereon. The two-layer sheet placed onthe copper foil was exposed to light with the photo mask placed thereon(Light Exposure Condition: light of 400 nm was applied by 300 mJ/cm²).After that, the PET film was peeled off therefrom. Then, thephotosensitive film on the copper foil was developed with 1% KOH aqueoussolution (at a liquid temperature of 40° C.). The photosensitive film onthe copper foil was then cured at 180° C. for 2 hours. The patternformed on the photosensitive film thus prepared was observed under amicroscope. The microscopic observation showed that the pattern ofline/space=100/100 μm was formed thereon.

Example 4

[0487] Example 4 was carried out in the same manner as Example 1, exceptthat a raw material compositional ratio for a silicone polyimide inExample 4 was as follows:

[0488] That is, 17.20 g (0.04 mol) of BAPS-M; 24.9 g (0.03 mol) ofsiloxanediamine (KF-8010 made by Shin-Etsu Silicone), 57.65 g (0.10 mol)of ESDA, 8.6 g (0.03 mol) of bis(4-amino-3carboxy-phenyl)methane.

[0489] A polyamic acid thus prepared had an Mw of 59,000. The polyamicacid was imidized as in Example 1, thereby obtaining 104 g of a (A)soluble polyimide (COOH equivalent: 1746).

[0490] As in Example 1, a two-layer sheet (laminate) structured asphotosensitive film (38 μm in thickness)/PET film (25 μm in thickness).Then, again as in Example 1, a flexible copper-clad laminate wasprepared.

[0491] The flexible copper-clad laminate had a peel adhesion strength of11.8 N/cm (1.2 kg weight/cm). Moreover, it was observed that 1-minuteimmersion of the flexible copper-clad laminate in a solder bath at 260°C. gave no defect such as swelling and the like to the flexiblecopper-clad laminate.

[0492] Moreover, the copper foil was removed from the flexiblecopper-clad laminate by etching, thereby obtaining a curedphotosensitive film (cover lay film). It was found that the cover layfilm had a degree of elasticity of 1,0000N/mm², extension of 25%, and athormolysis starting temperature of 370° C.

[0493] Furthermore, an FPC was prepared as in Example 1, and aninsulating resistance of the FPC was measured, the FPC having beensubjected to 24-hour moisture conditioning carried out under thefollowing conditions:

[0494] (1) Normal Condition: after moistening at 20° C. in 65% RH for 24hrs: =6×10¹⁵ Ω.

[0495] (2) Moisture Condition: after moistening at 35° C. in 85% RH for24 hrs: =2×10¹⁵ Ω.

[0496] Moreover, the two-layer sheet was placed on a copper foil so thatthe photosensitive film and the PET film were laminated in this order.Then, laminating process of the two-layer sheet placed on the copperfoil was carried out by applying a temperature of 100° C. and a force of100N/cm. After the laminating process, a photo mask having a pattern ofline/space=100/100 μm was placed thereon. The two-layer sheet placed onthe copper foil was exposed to light with the photo mask placed thereon(Light Exposure Condition: light of 400 nm was applied by 300 mJ/cm2).After that, the PET film was peeled off therefrom. Then, thephotosensitive film on the copper foil was developed with 1% KOH aqueoussolution (at a liquid temperature of 40° C.). The photosensitive film onthe copper foil was then cured at 180° C. for 2 hours. The patternformed on the photosensitive film thus prepared was observed under amicroscope. The microscopic observation showed that the pattern ofline/space=100/100 μm was formed thereon.

Comparative Example 1

[0497] Comparative Example 1 was carried out as in Example 1, exceptthat a raw material compositional ratio for a silicone polyimide inComparative Example 1 was as follows:

[0498] 17.20 g (0.04 mol) of BAPS-M; 24.9 g (0.03 mol) ofsiloxanediamine (KF-8010 made by Shin-Etsu Silicone); and 57.65 g (0.10mol) of ESDA.

[0499] A polyamic acid thus prepared had an Mw of 90,000. The polyamicacid was imidized as in Example 1, thereby obtaining a (A) solublepolyimide 95 g (COOH equivalent: infinite).

[0500] As in Example 1, a two-layer sheet (laminate) was prepared asphotosensitive polyimide/PET film. Then, again as in Example 1, aflexible copper-clad laminate was prepared.

[0501] The flexible copper-clad laminate had a peel adhesion strength of3.9N/cm (0.4 kg weight/cm). Moreover, it was observed that 1-minuteimmersion of the flexible copper-clad laminate in a solder bath at 260°C. gave no defect such as swelling and the like to the flexiblecopper-clad laminate.

[0502] Moreover, the copper foil was removed from the flexiblecopper-clad laminate by etching, thereby obtaining a curedphotosensitive film (cover lay film). It was found that the cover layfilm had a degree of elasticity of 1,000N/mm², extension of 25%, and athormolysis starting temperature of 350° C.

[0503] Furthermore, an FPC was prepared as in Example 1, and aninsulating resistance of the FPC was measured, the FPC having beensubjected to 24-hour moisture conditioning carried out under thefollowing conditions:

[0504] (1) Normal Condition: after moistening at 20° C. in 65% RH for 24hrs: =6×10¹⁵ Ω.

[0505] (2) Moisture Condition: after moistening at 35° C. in 85% RH for24 hrs: =3×10¹⁵ Ω.

[0506] Moreover, the two-layer sheet was placed on a copper foil so thatthe photosensitive film and the PET film were laminated in this order.Then, laminating process of the two-layer sheet placed on the copperfoil was carried out by applying a temperature of 100° C. and a force of100N/cm. After the laminating process, a photo mask having a pattern ofline/space=100/100 μm was placed thereon. The two-layer sheet placed onthe copper foil was exposed to light with the photo mask placed thereon(Light Exposure Condition: light of 400 nm was applied by 300 mJ/cm2).After that, the PET film was peeled off therefrom. Then, thephotosensitive film on the copper foil was post-baked at 100° C. for 3minutes and developed with 1% KOH aqueous solution (at a liquidtemperature of 40° C.). However, no pattern was formed.

[0507] [Production of Photosensitive Film]

[0508] Unless otherwise specified, photosensitive films in Examples 5 to28, and Comparative Examples 2 to 14 were carried out as follows.

[0509] Into a varnish prepared by dissolving (A) soluble polyimide intoa mixture solvent of tetrahydrofuran (THF) and dioxolane to a 30% solidcontent by weight (Sc), a (B) (meth)acrylic compound, a (C) fireretardant, and a (D) photo reaction initiator were mixed, therebyobtaining a varnish of a photosensitive resin composition. The varnishof the photosensitive resin composition was applied onto a PET film(functioning as a supporting film; 25 μm in thickness) so that a film ofthe photosensitive resin composition would have a 25 μm thickness afterdried. Then, the photosensitive resin composition on the PET film wasdried at 65° C. for 5 minutes so as to remove an organic solvent. Inthis way, a two-layer sheet having a photosensitive film (photosensitivelayer) in the B stage condition.

[0510] Next, a protect film was laminated on the two-layer sheet,thereby obtaining a three-layer sheet. As the protect film, a protect(#6221F) film (50 μm in thickness) made by Sekisui Chemical Co., Ltd.was used. The protect (#6221F) film was a PE-PE+EVA coextrusion film.The laminating of the protect film was so performed that a (PE+EVA)surface of the protect film was in contact with a photosensitive filmsurface. Lamination condition was as follows: roll temperature was 40°C.; and nip pressure was 1,500 Pa·m.

[0511] [Evaluation of Properties of Photosensitive Film]

[0512] Unless otherwise specified, properties of the photosensitive filmin Examples 5 to 28, and Comparative Example 2 to 14 were carried out asfollows.

[0513] <Soldering Heat Resistance>

[0514] Firstly, an electrolytic copper foil (35 μm) cut into a squareshape of 5 cm×5 cm was soft-etched for 1 minute with a 10% sulfuric acidaqueous solution (soft etching is a step of removing an anti-rustingagent from a surface of the copper foil). After the soft-etching, thecopper foil is washed with water. Then, the surface of the copper foilwas washed with ethanol and acetone, and then dried. Next, a protectivefilm was removed from a three-layer sheet that had been cut into asquare shape of 4 cm×4 cm. On a glossy surface of the electrolyticcopper foil (that had been soft-etched), the sheet from which theprotective film had been removed was laminated, by applying atemperature of 100° C. and a force of 20,000 Pa·m, in such a manner thata photosensitive film surface thereof was on the glossy surface.Thereby, a laminate was prepared. A photosensitive film surface of thelaminate was exposed to light of a wavelength of 400 nm by 300 mJ/cm²,and then cured by heating the laminate at 180° C. for 2 hours. Thereby,a sample was prepared.

[0515] After (a) subjected to whether (1) Normal Condition: moisteningat 20° C. in 40% RH for 24 hrs, or (2) Moisture Condition: moistening at40° C. in 85% RH for 48 hrs, and then (b) immersed for 1 minute in meltsolder having a temperature of 270° C., the sample was observed in termsof whether or not a swelling and/or peeling-off occurred in a boundarybetween the copper foil and the cured film. The temperature of the meltsolder was elevated and the sample was dipped in the metal solder for 30seconds every 10° C., so as to find out up to which temperature nodefect occurred. A highest temperature up to which no defect occurredwas determined as a 30-sec dupable temperature.

[0516] <Chemical Resistance>

[0517] A copper-clad laminate (CCL) on which a pattern circuit made ofcopper and having a line width/space width=250 μm/250 μm was cut into asquare shape of 5 cm×5 cm. Then, onto a photosensitive film surface of athree-layer sheet (cut in a square shape of 4 cm×4 cm) from which aprotective film had been peeled off, the CCL was laminated, by applyinga temperature of 100° C. and a force of 20,000 Pa·m, in such a mannerthat the photosensitive film surface faces that surface of the CCL onwhich the circuit was provided. Thereby, a laminate was formed. Aphotosensitive film surface of the laminate thus formed was exposed tolight of wavelength of 400 nm by 300 mJ/cm². Then, the laminate wascured by heating the laminate at 180° C. for 2 hours.

[0518] A sample thus prepared was immersed in each of the followingchemicals for 15 minutes, the chemicals having a temperature of 25° C.Then, it was observed in terms of whether or not there is any defect onthe cured film. The chemicals used for this test were: (1) isopropanol(IPA), (2) methylethylketone (MEK), (3) hydrochloric acid of 2 mol/L (2N), (4) sulfuric acid of 1 mol/L (2 N), (5) an aqueous solution ofsodium hydroxide of 2 mol/L (2 N), (6) an alternative substance forchlorofluorocarbon (new flon HFC 134a) (Product name: aeroduster ZC-31(made by Futaba tool Corp.). Judged as “fail” were the followingsamples: a sample in which the photosensitive film was peeled off fromthe copper-clad laminate (CCL), a sample whose color was changed, and asample in which the photosensitive film was dissolved thereby thinningthe sample.

[0519] <Development Property>

[0520] A photosensitive film surface of a three-layer sheet from which aprotective film had been peeled off, was laminated on a glossy surfaceof an electrolysis copper foil by applying a temperature of 100° C. anda force of 20,000 Pa·m. Thereby, a laminate was prepared. A photomaskwas placed on a supporting film of the laminate. And then, the laminatewas exposed to light of wavelength of 400 nm by 300 mJ/cm². After thesupporting film was peeled off therefrom, the sample was developed with1% aqueous solution of potassium hydroxide (liquid temperature of 40°C.) by using a spray developing apparatus (Etching Machine ES-655D, madeby Sunhayato Corp.). The development was carried out at a spray pressureof 0.85 Mpa, and by exposing the sample to a developer for 2 minutes.The photomask placed on the photosensitive film prior to the lightexposure had a fine hole of a square shape sized 100 μm×100 μm. Afterthe development, the sample was washed with distilled water so as toremove the developer, then dried. If observation using an opticalmicroscope showed that the hole of the square shape sized 100 μm×100 μmwas developed, it was judged that the sample was “pass”.

[0521] <Flame Resistance Test>

[0522] A photosensitive film surface of a three-layer sheet from which aprotective film had been peeled off, was laminated on a polyimide film(Apical AH made by Kaneka Corp.) having a 25 μm thickness. Thelaminating process was carried out by applying a temperature of 100° C.and a force of 75,000 Pa·m. Thereby, a laminate was formed. Next, thelaminate was exposed to light of wavelength of 400 nm by 600 mJ/cm².Then, a supporting film was peeled off from the laminate. The laminatefrom which the supporting film had been peeled off was heated at 180° C.for 2 hours. Thereby, a laminate sample (polyimide film/cover lay film(cured photosensitive film)) was prepared.

[0523] The laminate sample was cut into a size of 1.27 cm width×12.7 cmlong. 20 pieces of the cut were thus prepared. 10 of the pieces weresubjected to condition (1) “at 23° C. and 50% relative humidity for 48hours”, and the other 10 of the pieces were subjected to condition (2)“at 70° C. for 168 hours”. After treated as such, the pieces was cooledfor 4 hours or longer, the pieces being contained in a desiccator inwhich anhydrous calcium chloride was placed.

[0524] The samples thus prepared were vertically held by clipping upperparts thereof by using clamps. Then, the samples were lit up byapproaching, to a lower part thereof, a burner flame for 10 seconds.After 10 seconds the burner flame was moved away. Then, it was measuredhow long it took to extinguish a flame of the sample or inflammation ofthe sample. A sample was judged as “pass” if achieving both that the 10pieces for each condition (conditions (1) and (2)) were extinguished, onaverage (average of 10 pieces), within 5 seconds after the burner flamewas moved away from the samples, and that each of the samples wasself-extinguished by extinguishing the flame or combustion within 10seconds at maximum. A sample was judged as “fail” if any one of thepieces was not extinguished within 10 seconds, or if at least one of thepieces was so combusted that the flame went up to the upper part thereofwhere the clamp was.

[0525] <Flexibility>

[0526] A photosensitive film surface of a three-layer sheet from which aprotective film had been peeled off, was laminated on a polyimide film(Apical AH made by Kaneka Corp.) having a 25 μm thickness. Thelaminating process was carried out by applying a temperature of 100° C.and a force of 75,000 Pa·m. Thereby, a laminate was formed. Next, thelaminate was exposed to light of wavelength of 400 nm by 300 mJ/cm².Then, a supporting film was peeled off from the laminate. The laminatefrom which the supporting film had been peeled off was heated at 180° C.for 2 hours thereby being cured. Thereby, a laminate sample (polyimidefilm/cover lay film (cured photosensitive film)) was prepared.

[0527] The laminate sample was cut into a size of 2 cm×10 cm.

[0528] Samples thus prepared were tested (1) by bending them by 180°with a photosensitive film surface facing outward, or (2) by bendingthem by 180° with a cover lay film surface facing inward. A sample wasjudged as “pass” when the sample had no defect, such as cracking on acured film, after bending of either way. If any defect occurred in thesample after bending of at least one of the ways, it was judged that thesample was “fail”.

Example 5

[0529] <Synthesis of (A) Soluble Polyimide>

[0530] Into a 500 ml separable flask provided with a stirring apparatus,17.3 g (0.03 mol) of (2,2′-bis(4-hydorxyphenyl)propanedibenzoate)-3,3′,4,4′-tetracarboxylic anhydride (ESDA), 30 g ofN,N′-dimethylformamide (DMF) were poured, and stirred with the stirringapparatus until being dissolved. Next, a solution thus prepared, asolution in which 5.15 g (0.018 mol) of[bis(4-amino-3-carboxy)phenyl]methane (MBAA) made by Wakayama SeikaKogyo Ltd. was dissolved in 9 g of DMF was added. After that, thesolution was stirred vigorously.

[0531] To the solution that had been mixed thoroughly, 7.47 g (0.009mol) of KF-8010 (made by Shin-Etsu Silicone) was further added, and thenthe solution was vigorous stirred. After the solution was mixedthoroughly, 1.29 g (0.003 mol) of bis[4-(3-aminophenoxy)phenyl]sulfone(BAPS-M) was added finally. Then, the solution was stirred for 1 hourvigorously.

[0532] A polyamide solution thus prepared was transferred into a vatcoated with a fluorine-based resin. The polyamide solution in the vatwas vacuum-dried at 200° C. for 2 hours under a pressure of 660 Pa byusing a vacuum oven. Thereby, 26.40 g of a polyimide was synthesized. 50g of the polyimide was dissolved into 100 g of tetrahydrofuran (at 20°C.). Because 50 g or more was dissolved, the polyimide was employable asa soluble polyimide of the present invention.

[0533] <Preparation of Photosensitive Film>

[0534] 15 g of the soluble polyimide was dissolved into 50 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%.

[0535] Into 80 g of a varnish of the soluble polyimide, the followingcomponents were mixed in the following amounts, thereby obtaining avarnish of a photosensitive resin composition. The soluble polyimide (bysolid content by weight): 60 parts by weight, Bisphenol A EO modified(m + n ≈ 30) diacrylate 10 parts (NK ester A-BPE-30 made byShin-Nakamura Chemical Co., by weight Ltd.): (where m and n arerecurring units of ethyleneoxide modified sites. Hereinafter, m and nmean the same in the following Examples and Comparative Examples),Tribromophenylacrylate (BR-31 made by Dai-Ichi 30 parts Kogyo SeiyakuCo., Ltd.): by weight, Bis (2,4,6-trimethylbenzoil)phenylphosphineoxide1 part (irgacure 819 made by Ciba Specialty Chemicals K.K.): by weight,

[0536] The varnish of the photosensitive resin composition was appliedto a PET film (having a 25 μm thickness; acting as a supporting film),so that a film of the varnish would be 25 μm in thickness after dried.Then, the varnish applied on the PET film was subjected to a temperatureof 65° C. for 5 minutes so as to remove an organic solvent therefrom.Thereby, a two-layer sheet consistent of a photosensitive film and thePET film (supporting film) was prepared.

[0537] <Preparation of Laminate>

[0538] After that, a PE-PE+EVA co extruded film (protect (#6221F) filmmade by Sekisui Chemical Co., Ltd. (having a thickness of 50 μm)) waslaminated, as a protective film, on the two-layer sheet in such a mannerthat a (PE+EVA) copolymerization film surface was in contact with aphotosensitive film surface. Thereby, a three-layer sheet (laminate)structured as a supporting film/photosensitive cover lay film/protectivefilm. Laminating process was carried out at a roll temperature of 40° C.and a nip pressure of 1,500 Pa·m.

[0539] <Evaluation Result of Laminate>

[0540] Soldering heat resistance test of the laminate showed that thelaminate got a “pass” until 360° C. under the Normal Condition, anduntil 350° C. under the Moisture Condition.

[0541] Chemical resistance test of the laminate showed that the laminatewas resistant against all of the chemicals (1) to (6), and thus “pass”for all of the chemicals (1) to (6).

[0542] Development test of the laminate showed that a hole of a squareshape sized 100 μm×100 μm was developed successfully, and the laminategot a “pass”.

Example 6

[0543] <Synthesis of Modified Polyimide>20.5 g (0.020 mol) of thepolyimide synthesized in Example 5 was dissolved in 80 g of dioxolane.Then, 0.03 g of 4-methoxy phenol was added therein, and dissolved bymoderately heating by using an oil bath of 60° C. Into the solution, asolution prepared by dissolving 3.75 g (0.0264 mol) of glycidylmethacylate in 5 g of dioxolane was added. Further, 0.01 g oftriethylamine was added as a catalyst in the solution. Then, thesolution was stirred at 60° C. for 6 hours. Thereby a modified polyimidewas synthesized.

[0544] <Preparation of Photosensitive Film>

[0545] The following components in the following amounts were addedtherein, thereby obtaining a photosensitive resin composition. Then, athree-layer sheet (laminate) was prepared in the same fashion as above.The modified polyimide (by solid content by weight): 50 parts by weight,Bisphenol A EO modified (m + n ≈ 30) diacrylate 5 parts (NK esterA-BPE-30 made by Shin-Nakamura Chemical Co., by weight, Ltd.): BisphenolF EO modified (m + n ≈ 4) diacrylate 15 parts (allonix M-208 made byToagosei Co., Ltd.): by weight, Tribromophenylacrylate (BR-31 made byDai-Ichi 30 parts Kogyo Seiyaku Co., Ltd.): by weight,4,4′-bis(diethylamino)benzophenone: 1 part by weight,3,3′,4,4′,-tetra(t-butylperoxycarbonyl) 1 part benzophenone: by weight.

[0546] <Evaluation Result of Laminate>

[0547] Soldering heat resistance test of the laminate showed that thelaminate got a “pass” until 360° C. under the Normal Condition, anduntil 350° C. under the Moisture Condition.

[0548] Chemical resistance test of the laminate showed that the laminatewas resistant against all of the chemicals (1) to (6), and thus “pass”for all of the chemicals (1) to (6).

[0549] Development test of the laminate showed that a hole of a squareshape sized 100 μm×100 μm was developed successfully, and the laminategot a “pass”.

Example 7

[0550] As raw materials of a polyimide,3,3′,4,4′-biphenylethertetracarboxylic anhydride (ODPA) was used. Asdiamines, BAPS-M, MBAA, and KF-8010 mentioned above were used. Assolvent, N,N′-dimethylformamide(DMF) and dioxolane were used.

[0551] <Synthesis of Polyimide>

[0552] Into a 500 ml separable flask provided with a stirring apparatus,9.31 g (0.03 mol) of ODPA, and 30 g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. Next, into the solutionthus prepared, a solution prepared by dissolving 4.29 g (0.015 mol) ofMBAA in 10 g of DMF was added as a diamine. Then, the solution wasvigorously stirred. After the solution was thoroughly mixed, 7.47 g(0.009 mol) of KF-8010 (made by Shin-Etsu Silicone) was added assiloxanediamine. Then, the solution was vigorously stirred. After thesolution was thoroughly mixed, 2.58 g (0.006 mol) of BAPS-M was finallyadded. Then, the solution was vigorously stirred for 1 hour.

[0553] A polyamide solution thus prepared was transferred into a vatcoated with a fluorine-based resin. The polyamide solution in the vatwas vacuum-dried at 200° C. for 2 hours under a pressure of 660 Pa byusing a vacuum oven. Thereby, 21.28 g of a polyimide was synthesized.

[0554] 50 g or more of the polyimide was dissolved into 100 g oftetrahydrofuran at 20° C. Because 50 g or more was dissolved, thepolyimide was a soluble polyimide defined in the present invention.

[0555] <Preparation of Photosensitive Film>

[0556] 21 g of the soluble polyimide was dissolved into 49 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%.

[0557] Into 73 g of a varnish of the soluble polyimide, the followingcomponents were mixed in the following amounts, thereby obtaining avarnish of a photosensitive resin composition. The soluble polyimide (bysolid content by weight): 55 parts by weight. Bisphenol A EO modified(m + n ≈ 30) diacrylate 10 parts (NK ester A-BPE-30 made byShin-Nakamura Chemical Co., by weight, Ltd.): Bisphenol F EO modified(m + n ≈ 4) diacrylate 20 parts (allonix M-208 made by Toagosei Co.,Ltd.): by weight, Siloxane compound (XC99-B5664 made by Toshiba 15 partssilicones): by weight, 4,4′-bis(diethylamino)benzophenone: 1 part byweight, 3,3′,4,4′,-tetra(t-butylperoxycarbonyl) 1 part benzophenone: byweight.

[0558] <Evaluation Result of Photosensitive Film>

[0559] A photosensitive film (laminate) was prepared from thephotosensitive resin composition in the same fashion as above. Solderingheat resistance test of the photosensitive film showed that the laminategot a “pass” until 360° C. under the Normal. Condition, and until 330°C. under the Moisture Condition.

[0560] Chemical resistance test of the photosensitive film showed thatthe laminate was resistant against all of the chemicals (1) to (6), andthus “pass” for all of the chemicals (1) to (6).

[0561] Development test of the photosensitive film showed that a hole ofa square shape sized 100 μm×100 μm was developed successfully, and thephotosensitive film got a “pass”.

Example 8

[0562] As a raw material of a polyimide,3,3′,4,4′-biphenylsulphonetetracarboxylic anhydride (DSDA) was used. Asdiamines, BAPS-M, MBAA, and KF-8010 mentioned above were used. Assolvent, N,N′-dimethylformamide(DMF) and dioxolane were used.

[0563] <Synthesis of Polyimide>

[0564] Into a 500 ml separable flask provided with a stirring apparatus,10.75 g (0.030 mol) of DSPA, and 30 g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. Next, into the solutionthus prepared, a solution prepared by dissolving 4.29 g (0.015 mol) ofMBAA, made by Wakayama Seika Kogyo Ltd., in 10 g of DMF was added. Then,the solution was vigorously stirred. After the solution was thoroughlymixed, 7.47 g (0.009 mol) of KF-8010 (made by Shin-Etsu Silicone) wasadded as siloxanediamine. Then, the solution was vigorously stirred.After the solution was thoroughly mixed, 2.58 g (0.006 mol) of BAPS-Mwas finally added. Then, the solution was vigorously stirred for 1 hour.A polyamide solution thus prepared was transferred into a vat coatedwith a fluorine-based resin. The polyamide solution in the vat wasvacuum-dried at 200° C. for 2 hours under a pressure of 660 Pa by usinga vacuum oven. Thereby, 22.57 g of a polyimide was synthesized. 50 g ormore of the polyimide was dissolved into 100 g of tetrahydrofuran at 20°C. Because 50 g or more was dissolved, the polyimide was a solublepolyimide defined in the present invention.

[0565] <Preparation of Photosensitive Film>

[0566] 21 g of the soluble polyimide was dissolved into 49 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%.

[0567] Into 53 g of a varnish of the soluble polyimide, the followingcomponents were mixed in the following amounts, thereby obtaining avarnish of a photosensitive resin composition. The soluble polyimide (bysolid content by weight): 40 parts by weight, Bisphenol A EO modified(m + n ≈ 30) diacrylate 5 parts (NK ester A-BPE-30 made by Shin-NakamuraChemical Co., by weight, Ltd.): Bisphenol F EO modified (m + n ≈ 4)diacrylate 30 parts (allonix M-208 made by Toagosei Co., Ltd.): byweight, Tribromophenylacrylate (BR-31 made by Dai-Ichi 25 parts KogyoSeiyaku Co., Ltd.): by weight, 4,4′-bis(diethylamino)benzophenone: 1part by weight, 3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone: 1part by weight.

[0568] <Evaluation Result of Photosensitive Film>

[0569] A photosensitive film (laminate) was prepared from thephotosensitive resin composition in the same fashion as above. Solderingheat resistance test of the photosensitive film showed that the laminategot a “pass” until 350° C. under the Normal Condition, and until 340° C.under the Moisture Condition.

[0570] Chemical resistance test of the photosensitive film showed thatthe laminate was resistant against all of the chemicals (1) to (6), andthus “pass” for all of the chemicals (1) to (6). Development test of thephotosensitive film showed that a hole of a square shape sized 100μm×100 μm was developed successfully, and the photosensitive film got a“pass”.

Example 9

[0571] As raw materials of a polyimide,4,4′-(4,4′-isopropylidenediphenoxy)bisphthalic anhydride (BSAA), and3.3°,4,4′-biphenyltetracarboxilic dianhydride (s-BPDA) were used. Asdiamines, BAPS-M, MBAA, and KF-8010 mentioned above were used. Assolvent, N,N′-dimethylformamide (DMF) and dioxolane were used.

[0572] <Synthesis of Polyimide>

[0573] Into a 500 ml separable flask provided with a stirring apparatus,26.02 g (0.050 mol) of BSAA, and 30 g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. After dissolved, into thesolution thus prepared, a solution prepared by dissolving 14.71 g (0.050mol) of s-BPDA and 20 g of DMF were added. Then, the solution wasfurther stirred vigorously. Then, into the solution thus prepared, asolution prepared by dissolving 14.30 g (0.050 mol) of MBAA, made byWakayama Seika Kogyo Ltd., in 30 g of DMF was added. Then, the solutionwas vigorously stirred. After the solution was thoroughly mixed, 24.90 g(0.030 mol) of KF-8010 (made by Shin-Etsu Silicone) was added assiloxanediamine. Then, the solution was vigorously stirred. After thesolution was thoroughly mixed, 8.61 g (0.020 mol) of BAPS-M was finallyadded. Then, the solution was vigorously stirred for 1 hour. A polyamidesolution thus prepared was transferred into a vat coated with afluorine-based resin. The polyamide solution in the vat was vacuum-driedat 200° C. for 2 hours under a pressure of 660 Pa by using a vacuumoven. Thereby, 80.0 g of a polyimide was synthesized.

[0574] 50 g or more of the polyimide was dissolved into 100 g oftetrahydrofuran at 20° C. Because 50 g or more was dissolved, thepolyimide was a soluble polyimide defined in the present invention.

[0575] <Preparation of Photosensitive Film>

[0576] 21 g of the soluble polyimide was dissolved into 49 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%.

[0577] A photosensitive resin composition was prepared by mixing thesame components in the same way as in Example 8, except that a polyimide(a copolymer of two kinds of acid dianhydrides) thus synthesized by theabove mentioned method was used instead of the polyimide of Example 8.Then, a photosensitive film (laminate) was prepared by the methodmentioned above.

[0578] <Evaluation Result of Photosensitive Film>

[0579] Soldering heat resistance test of the photosensitive film showedthat the laminate got a “pass” until 340° C. under the Normal Condition,and until 330° C. under the Moisture Condition.

[0580] Chemical resistance test of the photosensitive film showed thatthe laminate was resistant against all of the chemicals (1) to (6), andthus “pass” for all of the chemicals (1) to (6). Development test of thephotosensitive film showed that a hole of a square shape sized 100μm×100 μm was developed successfully, and the photosensitive film got a“pass”.

Example 10

[0581] As raw materials of a polyimide, BSAA, s-BPDA, BAPS-M, KF-8010,and 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane were used. Assolvent, N,N′-dimethylformamide (DMF) and dioxolane were used.

[0582] <Synthesis of Polyimide>

[0583] Into a 500 ml separable flask provided with a stirring apparatus,26.02 g (0.050 mol) of BSAA, and 30 g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. After dissolved, into thesolution thus prepared, a solution prepared by dissolving 14.71 g (0.050mol) of s-BPDA in 20 g of DMF was added. Then, the solution wasvigorously stirred. Into the solution that had been thoroughly mixed, asolution prepared by dissolving 18.31 g (0.050 mol) of diamine(2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane) in 30 g of DMF wasadded. Then, the solution was vigorously stirred. When the solution wasthoroughly mixed, 24.90 g (0.030 mol) of KF-8010 (made by Shin-EtsuSilicone) was added as siloxanediamine. Then, the solution wasvigorously stirred. After the solution was thoroughly mixed, 8.61 g(0.020 mol) of BAPS-M was finally added. Then, the solution wasvigorously stirred for 1 hour. A polyamide solution thus prepared wastransferred into a vat coated with a fluorine-based resin. The polyamidesolution in the vat was vacuum-dried at 200° C. for 2 hours under apressure of 660 Pa by using a vacuum oven. Thereby, 83.5 g of apolyimide was synthesized.

[0584] 50 g or more of the polyimide was dissolved into 100 g oftetrahydrofuran at 20° C. Because 50 g or more was dissolved, thepolyimide was a soluble polyimide defined in the present invention.

[0585] <Preparation of Photosensitive Film>

[0586] 30 g of the soluble polyimide was dissolved into 70 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%.

[0587] A photosensitive resin composition was prepared by mixing thesame components in the same way as in Example 8, except that a polyimidethus synthesized by the above mentioned method was used instead of thepolyimide of Example 8. Then, a photosensitive film (laminate) wasprepared by the method mentioned above.

[0588] <Evaluation Result of Photosensitive Film>

[0589] Soldering heat resistance test of the photosensitive film showedthat the laminate got a “pass” until 350° C. both under the NormalCondition, and under the Moisture Condition.

[0590] Chemical resistance test of the photosensitive film showed thatthe laminate was resistant against all of the chemicals (1) to (6), andthus “pass” for all of the chemicals (1) to (6). Development test of thephotosensitive film showed that a hole of a square shape sized 100μm×100 μm was developed successfully, and the photosensitive film got a“pass”.

Comparative Example 2

[0591] A photosensitive resin composition was prepared by mixing thefollowing components in the following amounts. Then, a photosensitivefilm (laminate) was prepared in the above-mentioned method. A copolymersynthesized by copolymerizing 50 parts methylmethacrylate,n-butylmethacrylate, by weight, 2-ethylhexylacrylate, and methacrylicacid, in a copolymerization ratio (by weight) of 55:8:15:22: Bisphenol AEO modified (m + n ≈ 30) diacrylate 10 parts (NK ester A-BPE-30 made byShin-Nakamura Chemical Co., by weight, Ltd.): Bisphenol F EO modified(m + n ≈ 4) diacrylate 10 parts (allonix M-208 made by Toagosei Co.,Ltd.): by weight, Tribromophenylacrylate (BR-31 made by Dai-Ichi 30parts Kogyo Seiyaku Co., Ltd.): by weight,Bis(2,4,6-trimethylbenzoil)phenylphosphineoxide 1 part (irgacure 819made by Ciba Specialty Chemicals K.K.): by weight.

[0592] Soldering heat resistance test of the photosensitive film got a“pass” until 280° C. under the Normal Condition, and until 250° C. underthe Moisture Condition. Thus, the photosensitive film was poor in theheat resistance.

[0593] Moreover, as to chemical resistance test, the photosensitive filmgot a “pass” for (3) hydrochloric acid of 2 mol/L and (4) sulfuric acidof lmol/L. However, the photosensitive film was swollen when immersed in(1) isopropanol (IPA) and (2) methylethylketone (MEK). When immersed in(5) aqueous solution of sodium hydroxide of 2 mol/L, the photosensitivefilm was dissolved, thereby reducing its thickness by 40% or more. Thus,the photosensitive film got a “fail” for those chemicals. Indevelopment. Development test of the laminate showed that a hole of asquare shape sized 100 μm×100 μm was developed successfully, and thephotosensitive film got a “pass”.

[0594] As described above, the photosensitive film prepared from thecopolymer that is not a polyimide was poor in the heat resistance andthe chemical resistance.

Comparative Example 3

[0595] A photosensitive resin composition was prepared by mixing thefollowing components in the following amounts. Then, a photosensitivefilm (laminate) was prepared in the above-mentioned method. A copolymersynthesized by copolymerizing 60 parts methylmethacrylate,n-butylmethacrylate, by weight, 2-ethylhexylacrylate, and methacrylicacid, in a copolymerization ratio (by weight) of 55:8:15:22: Bisphenol FEO modified (m + n ≈ 4) diacrylate 15 parts (allonix M-208 made byToagosei Co., Ltd.): by weight, Epoxy resin (epicoat 828 made ToagoseiCo., Ltd.): 5 parts by weight, tribromophenylacrylate (BR-31 made byDai-Ichi 15 parts Kogyo Seiyaku Co., Ltd.): by weight,Bis(2,4,6-trimethylbenzoil)phenylphosphineoxide 1 part (irgacure 819made by Ciba Specialty Chemicals K.K.): by weight.

[0596] Soldering heat resistance test of the photosensitive film got a“pass” until 310° C. under the Normal Condition, and until 280° C. underthe Moisture Condition. Thus, the photosensitive film was poor in theheat resistance.

[0597] Moreover, as to chemical resistance test, the photosensitive filmgot a “pass” for (3) hydrochloric acid of 2 mol/L and (4) sulfuric acidof lmol/L. However, the photosensitive film was peeled off when immersedin (1) isopropanol (IPA). The photosensitive film was swollen whenimmersed in (2) methylethylketone (MEK). When immersed in (5) aqueoussolution of sodium hydroxide of 2 mol/L, the photosensitive film wasdissolved, thereby reducing its thickness by 40% or more. Thus, thephotosensitive film got a “fail” for those chemicals. In developing.Development test of the laminate showed that a hole of a square shapesized 100 μm×100 μm was developed successfully, and the photosensitivefilm got a “pass”.

[0598] As described above, the photosensitive film prepared from acopolymer that is not a polyimide was poor in the heat resistance andthe chemical resistance.

Example 11

[0599] As raw materials of a polyimide, BAPS-M, MBAA, KF-8010 were used.As solvent, N,N′-dimethylformamide (DMF) and dioxolane were used.

[0600] <Synthesis of Polyimide>

[0601] Into a 500 ml separable flask provided with a stirring apparatus,17.3 g (0.030 mol) of ESDA, and 30 g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. After dissolved, into thesolution thus prepared, a solution prepared by dissolving 5.15 g (0.018mol) of diamine MBAA (made by Wakayama Seika Kogyo Ltd.) in 9 g of DMFwas added. Then, the solution was vigorously stirred. When the solutionwas thoroughly mixed, 7.47 g (0.009 mol) of KF-8010 (made by Shin-EtsuSilicone) was added as siloxanediamine. Then, the solution wasvigorously stirred. After the solution was thoroughly mixed, 1.29 g(0.003 mol) of BAPS-M was finally added. Then, the solution wasvigorously stirred for 1 hour. A polyamide solution thus prepared wastransferred into a vat coated with a fluorine-based resin. The polyamidesolution in the vat was vacuum-dried at 200° C. for 2 hours under apressure of 660 Pa by using a vacuum oven. Thereby, 26.40 g of a solublepolyimide was obtained.

[0602] 50 g or more of the polyimide was dissolved into 100 g oftetrahydrofuran (at 20° C.). Because 50 g or more was dissolved, thepolyimide came under a soluble polyimide defined in the presentinvention.

[0603] <Production of Laminate>

[0604] 15 g of the soluble polyimide was dissolved into 35 g ofdioxolane, thereby preparing a varnish of a solid content % by weight(Sc) of 30%.

[0605] A photosensitive resin composition was prepared by mixing thefollowing components in the following amounts. Then, the photosensitiveresin composition was applied on a PET film in the method mentionedabove, thereby obtaining a photosensitive film in the B stage condition.Further, a protective film was laminated on the photosensitive film,thereby obtaining a three-layer sheet (laminate) of PETfilm/photosensitive film/protective film. The soluble polyimide (bysolid content by weight) 50 parts by weight, Imidoacrylate (allonixTO-1429, made by Toagosei 40 parts by weight: Co., Ltd.) represented bythe following formula (119) (119)

Bisphenol A EO modified (recurring units of 10 parts by weight,ethyleneoxide modified sites; m + n ≈ 4) diacrylate (allonix M-211B,made by Toagosei Co., Ltd.):Bis(2,4,6-trimethylbenzoil)phenylphosphineoxide  1 part by weight.(irgacure 819 made by Ciba Specialty Chemicals K.K.):

[0606] The photosensitive film had a compression-bondable temperature of120° C. with respect to a polyimide film and a glossy surface of acopper foil. Soldering heat resistance test of the photosensitive filmshowed that the photosensitive film got a “pass” until 370° C. under theNormal Condition, and until 360° C. under the Moisture Condition.Moreover, flame resistance test of the photosensitive film showed thatthe photosensitive film was extinguished in 4.5 seconds on average andgot a “pass”. Further, flexibility test of the photosensitive filmshowed that no crack was caused in the photosensitive film, thus thephotosensitive film got a “pass”. Development test of the photosensitivefilm showed that a hole of a square shape sized 100 μm×100 μm wasdeveloped successfully, and the photosensitive film got a “pass”.

Example 12

[0607] <Sythesis of Modified Polyimide>

[0608] 20.8 g (0.020 mol) of the polyimide synthesized in Example 11 wasdissolved in 80 g of dioxolane. Then, 0.030 g of 4-methoxyphenol wasadded therein, and dissolved by moderately heating by using an oil bathof 60° C. Into a solution thus prepared, a solution thus prepared bydissolving 3.75 g (0.0264 mol) of glycidyl methacrylate in 5 g ofdioxolane. Further, 0.01 g of triethylamine was added therein as acatalyst. Then, a solution thus prepared was heated at 60° C. for 6hours with stirring. Thereby, a modified polyimide was synthesized.

[0609] <Preparation of Photosensitive Film>

[0610] A photosensitive resin composition was prepared by mixing thefollowing components in the following amounts. Then, a three-layer sheet(laminate) was prepared in the above-mentioned method. The modifiedpolyimide (by solid content by 60 parts weight): by weight,Imideacrylate (allonix TO-1429, made by Toagosei 20 parts Co., Ltd.): byweight, Bisphenol A EO modified (recurring units of 10 partsethyleneoxide modified sites; m + n ≈ 30) diacrylate (NK by weight,ester A-BPE-30, made by Shin-Nakamura Chemical Co., Ltd.):Bis(2,4,6-trimethylbenzoil)phenylphosphineoxide 1 part (irgacure 819made by Ciba Specialty Chemicals K.K.): by weight, Bis(2-vinylphenoxy)phosphazen (polymerization 10 parts degree of 3): by weight.

[0611] The photosensitive film had a compression-bondable temperature of100° C. with respect to a polyimide film and a glossy surface of acopper foil. Soldering heat resistance test of the photosensitive filmshowed that the photosensitive film got a “pass” until 360° C. under theNormal Condition, and until 350° C. under the Moisture Condition.Moreover, flame resistance test of the photosensitive film showed thatthe photosensitive film was extinguished in 4.0 seconds on average andgot a “pass”. Further, flexibility test of the photosensitive filmshowed that utterly no crack was caused in the photosensitive film, thusthe photosensitive film got a “pass”. Development test of thephotosensitive film showed that a hole of a square shape sized 100μm×100 μm was developed successfully, and the photosensitive film got a“pass”.

Example 13

[0612] As a raw material of a polyimide,3,3′,4,4′-biphenylethertetracarboxylic anhydride (ODPA) was used. Asdiamines, BAPS-M, MBAA, And KF-8010 mentioned above were used. Assolvents, N,N′-dimethylformamide (DMF) and dioxolane were used.

[0613] <Synthesis of Polyimide>

[0614] Into a 500 ml separable flask provided with a stirring apparatus,9.31 g (0.030 mol) of ODPA, and 30 g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. After dissolved, into thesolution thus prepared, a solution prepared by dissolving 4.29 g (0.015mol) of diamine MBAA (made by Wakayama Seika Kogyo Ltd.) in 10 g of DMFwas added. Then, the solution was vigorously stirred. When the solutionwas thoroughly mixed, 7.47 g (0.009 mol) of KF-8010 (made by Shin-EtsuSilicone) was added as siloxanediamine. Then, the solution wasvigorously stirred. After the solution was thoroughly mixed, 2.58 g(0.006 mol) of BAPS-M was finally added. Then, the solution wasvigorously stirred for 1 hour. A polyamide solution thus prepared wastransferred into a vat coated with a fluorine-based resin. The polyamidesolution in the vat was vacuum-dried at 200° C. for 2 hours under apressure of 660 Pa by using a vacuum oven. Thereby, 21.28 g of a solublepolyimide was obtained.

[0615] 50 g or more of the polyimide was dissolved into 10 g oftetrahydrofuran (at 20° C.). Because 50 g or more was dissolved, thepolyimide came under a soluble polyimide defined in the presentinvention.

[0616] <Preparation of Photosensitive Film>

[0617] 21 g of the soluble polyimide was dissolved into 49 g ofdioxolane, thereby preparing a varnish of a solid content % by weight(Sc) of 30%.

[0618] A photosensitive resin composition was prepared by mixing thefollowing components in the following amounts. Then, a photosensitivefilm was prepared by the method described above. The soluble polyimide(by solid content by weight): 40 parts by weight, Imidoacrylate (allonixTO-1429, made by Toagosei 30 parts Co., Ltd.): by weight, Bisphenol A EOmodified (m + n ≈ 4) diacrylate 10 parts (allonix M-211B, made byToagosei Co., Ltd.): by weight,Bis(2,4,6-trimethylbenzoil)phenylphosphineoxide 1 part (irgacure 819made by Ciba Specialty Chemicals K.K.): by weight, EO modifiedtribromophenylacrylate (BR-31, made 20 parts by Dai-Ichi Kogyo SeiyakuCo., Ltd.) by weight.

[0619] The photosensitive film had a compression-bondable temperature of90° C. with respect to a polyimide film and a glossy surface of a copperfoil. Soldering heat resistance test of the photosensitive film showedthat the photosensitive film got a “pass” until 360° C. under the NormalCondition, and until 350° C. under the Moisture Condition. Moreover,flame resistance test of the photosensitive film showed that thephotosensitive film was extinguished in 2.0 seconds on average and got a“pass”. Further, flexibility test of the photosensitive film showed thatutterly no crack was caused in the photosensitive film, thus thephotosensitive film got a “pass”. Development test of the photosensitivefilm showed that a hole of a square shape sized 100 μm×100 μm wasdeveloped successfully, and the photosensitive film got a “pass”.

Example 14

[0620] <Synthesis of N-(Acryloyloxy)-4-methyl Hexahydrophthalimide>

[0621] 16 ml (0.26 mol) of hydroxylamine (50% aqueous solution thereof)was poured into a 100 ml flask. Then, 33.4 g (0.2 mol) of4-methylhexahydrophthalic anhydride was dropped in at a room temperaturewith stirring. After the dropping, a solution thus prepared wasgradually heated and reacted for 1 hour at 100° C. After the reaction, ahydrochloric acid aqueous solution of 4 mol/L (4 N) was added into areaction liquid, thereby acidifying the reaction liquid.

[0622] A target substance was extracted from thus prepared reactionmixture by using chloroform, and an organic layer was separated. Theorganic layer was dried with anhydrous magnesium sulfate. Then,chloroform was separated from the reaction mixture, thereby obtaining32.4 g (yield 89%) of N-hydroxy-4-methylhexahydrophthalimide (a viscousliquid of transparent and colorless).

[0623] Next, 10.07 g (0.055 mol) ofN-hydroxy-4-methylhexahydrophthalimide, 15 ml (0.1 lmol) oftriethylamine, and 50 ml of 1,2-dichloroethane were poured in a 100 mlflask. Then, 7.2 ml (0.090 mol) of acrylyl chloride was slowly droppedtherein at a room temperature under nitrogen with stirring. After thedropping, a mixture thus prepared was reacted for one hour at a roomtemperature. A reaction mixture was washed with water so as to separatean organic layer therefrom. Then, the organic layer was washed with a 5%sodium hydrogen carbonate aqueous solution. The organic layer separatedfrom the 5% sodium hydrogen carbonate aqueous solution was dried withmagnesium sulfate, and then a solvent was removed from the organiclayer. 11.8 g of N-(acryloyloxy)-4-methylhexahydrophthalimide (viscousliquid of dark yellow color) was thereby obtained.N-(acryloyloxy)-4-methylhexahydrophthalimide is represented by thefollowing formula (120):

[0624] <Preparation of Photosensitive Film>A photosensitive resincomposition was prepared by mixing the same component in the same manneras in Example 12, except thatN-(acryloyloxy)-4-methylhexahydrophthalimide thus synthesized above wasused as an imide acrylate. Then, a photosensitive film was prepared inthe fashion mentioned above.

[0625] The photosensitive film had a compression-bondable temperature of100° C. with respect to a polyimide film and a glossy surface of acopper foil. Soldering heat resistance test of the photosensitive filmshowed that the photosensitive film got a “pass” until 360° C. under theNormal Condition, and until 350° C. under the Moisture Condition.Moreover, flame resistance test of the photosensitive film showed thatthe photosensitive film was extinguished in 2.8 seconds on average andgot a “pass”. Further, flexibility test of the photosensitive filmshowed that utterly no crack was caused in the photosensitive film, thusthe photosensitive film got a “pass”. Development test of thephotosensitive film showed that a hole of a square shape sized 100μm×100 μm was developed successfully, and the photosensitive film got a“pass”.

Example 15

[0626] As a raw material of a polyimide,3,3′,4,4′-biphenylsulfonetetracarboxylic anhydride (DSDA) was used. Asdiamines, BAPS-M and MBAA were used. As solvents, N,N′-dimethylformamide(DMF) and dioxolane.

[0627] <Synthesis of Polyimide>

[0628] Into a 500 ml separable flask provided with a stirring apparatus,10.75 g (0.030 mol) of DSDA, and 30 g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. After dissolved, into thesolution thus prepared, a solution prepared by dissolving 4.29 g (0.015mol) of diamine MBAA (made by Wakayama Seika Kogyo Ltd.) in 10 g of DMFwas added. Then, the solution was vigorously stirred. When the solutionwas thoroughly mixed, 7.47 g (0.009 mol) of KF-8010 (made by Shin-EtsuSilicone) was added as siloxanediamine. Then, the solution wasvigorously stirred. After the solution was thoroughly mixed, 2.58 g(0.006 mol) of BAPS-M was finally added. Then, the solution wasvigorously stirred for 1 hour. A polyamide solution thus prepared wastransferred into a vat coated with a fluorine-based resin. The polyamidesolution in the vat was vacuum-dried at 200° C. for 2 hours under apressure of 660 Pa by using a vacuum oven. Thereby, 22.57 g of a solublepolyimide was obtained.

[0629] 50 g or more of the polyimide was dissolved into 100 g oftetrahydrofuran (at 20° C.). Because 50 g or more was dissolved, thepolyimide was employable as a soluble polyimide of the presentinvention.

[0630] <Preparation of Photosensitive Film>

[0631] 21 g of the soluble polyimide was dissolved into 49 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%.

[0632] By adding the following components in the following amount, aphotosensitive resin composition was prepared. Then, a photosensitivefilm was prepared by the method mentioned above. The soluble polyimide(by solid content by weight): 40 parts by weight,N-(acryloyloxy)-4-methylhexahydrophthalimide: 10 parts by weight,Bisphenol A EO modified (m + n ≈ 4) diacrylate 10 parts (allonix M-211B,made by Toagosei Co., Ltd.): by weight, Bis(2,4,6-trimethylbenzoil)phenylphosphineoxide 1 part (irgacure 819 madeby Ciba Specialty Chemicals K.K.): by weight, EO modifiedtribromophenylacrylate (BR-31, made 20 parts by Dai-Ichi Kogyo SeiyakuCo., Ltd.): by weight.

[0633] The photosensitive film had a compression-bondable temperature of130° C. with respect to a polyimide film and a glossy surface of acopper foil. Soldering heat resistance test of the photosensitive filmshowed that the photosensitive film got a “pass” until 360° C. under theNormal Condition, and until 350° C. under the Moisture Condition.Moreover, flame resistance test of the photosensitive film showed thatthe photosensitive film was extinguished in 4.0 seconds on average andgot a “pass”. Further, flexibility test of the photosensitive filmshowed that utterly no crack was caused in the photosensitive film, thusthe photosensitive film got a “pass”. Development test of thephotosensitive film showed that a hole of a square shape sized 100μm×100 μm was developed successfully, and the photosensitive film got a“pass”.

Example 16

[0634] <Synthesis of N-Acryloyloxyethylphthalic Imide>

[0635] Into a 100 ml flask, a solution of 14.81 g (0.10 mol) ofanhydrous phthalic acid was dissolved in 30 g of dioxolane was poured.Then, 6.11 g (0.10 mol) of amino ethanol was dropped therein at a roomtemperature with stirring. After the dropping, a solution thus preparedwas gradually heated and reacted at 60° C. for one hour. After thereaction, hydrochloric aqueous solution of 4 mol/L (4 N) was added intoa reaction liquid, which was thereby acidified. In this way,N-hydroxyethylphthalic imide (a colorless solid) was obtained. 16.71 g(0.087 mol) of N-hydroxyethylphthalic imide thus obtained, 9 ml (0.0066mol) of triethylamine, and 50 ml of 1,2-dichloroethane were poured intoa 100 ml flask. Then, 7.9 ml (0.090 mol) of acrylyl chloride was slowlydropped therein at a room temperature under nitrogen with stirring.After dropping, a solution thus prepared was reacted at a roomtemperature for one hour. After that, a reaction mixture was washed withwater so as to separate an organic layer. Then, the organic layer waswashed with a 5% sodium hydrogen carbonate aqueous solution. The organiclayer separated from the 5% sodium hydrogen carbonate aqueous solutionwas dried with magnesium sulfate, and then a solvent was removed fromthe organic layer. Thereby, 15.4 g of N-acryloyloxyethylphthalic imide(viscous liquid of dark yellow color) was obtained.N-acryloyloxyethylphthalic imide is represented by the following Formula(121):

[0636] Preparation of Photosensitive Film>

[0637] A photosensitive resin composition was prepared by mixing thesame component in the same manner as in Example 12, except thatN-acryloyloxyethylphthalic imide thus synthesided above was used as animide acrylate. Then, a photosensitive film was prepared in the fashionmentioned above.

[0638] The photosensitive film had a compression-bondable temperature of100° C. with respect to a polyimide film and a glossy surface of acopper foil. Soldering heat resistance test of the photosensitive filmshowed that the photosensitive film got a “pass” until 360° C. under theNormal Condition, and until 350° C. under the Moisture Condition.Moreover, flame resistance test of the photosensitive film showed thatthe photosensitive film was extinguished in 3.5 seconds on average andgot a “pass”. Further, flexibility test of the photosensitive filmshowed that utterly no crack was caused in the photosensitive film, thusthe photosensitive film got a “pass”. Development test of thephotosensitive film showed that a hole of a square shape sized 100μm×100 μm was developed successfully, and the photosensitive film got a“pass”.

Example 17

[0639] <Synthesis of N,N′-Bis(Acryloyxyethyl)Oxydiphthalic Imide>

[0640] Into a 100 ml flask, a solution prepared by dissolving 31.0 g(0.1 mol) of 3,3′,4,4′-biphenylethertetracarboxylic anhydride (ODPA) in30 g of dioxolane was poured. 15.9 g (0.26 mol) of aminoethanol wasdropped, at a room temperature, into the solution being stirred. Afterthe dropping, the solution thus prepared was gradually heated andreacted at 100° C. for 1 hour. After the reaction, hydrochloric aqueoussolution of 4 mol/L (4 N) was added in a reaction liquid, which wasthereby acidified. A target substance was extracted with chloroform froma reaction mixture thus prepared, thereby separating an organic layertherefrom. The organic layer was dried with anhydrous magnesium sulfate.Then, chloroform was removed from the organic layer. Thereby, 36.8 g(yield 93%) of N,N′-bis(hydroxyethyl)oxydiphthalic imide (viscous liquidof transparent and colorless) was obtained.

[0641] Next, 21.8 g (0.055 mol) of N,N′-bis(hydroxyethyl)oxydiphthalicimide, 15 ml (0.11 mol) of triethylamine, and 50 ml of1,2-dichloroethane were poured in a 100 ml flask. Then, 14.4 ml (0.180mol) of acrylyl chloride was slowly dropped therein at a roomtemperature under nitrogen with stirring. After the dropping, a mixturethus prepared was reacted for one hour at a room temperature. A reactionmixture was washed with water so as to separate an organic layertherefrom. Then, the organic layer was washed with a 5% sodium hydrogencarbonate aqueous solution. The organic layer separated from the 5%sodium hydrogen carbonate aqueous solution was dried with magnesiumsulfate, and then a solvent was removed from the organic layer. 20.8 gof N,N-bis(acryloyloxyethyl)oxydiphthalic imide (viscous liquid of darkyellow color) was thereby obtained.N,N-bis(acryloyloxyethyl)oxydiphthalic imide is represented by thefollowing formula (122):

[0642] <Preparation of Photosensitive Film>A photosensitive resincomposition was prepared by mixing the same component in the same manneras in Example 12, except that N,N-bis(acryloyloxyethyl)oxydiphthalicimide thus synthesized above was used as an imide acrylate. Then, aphotosensitive film was prepared in the fashion mentioned above.

[0643] The photosensitive film had a compression-bondable temperature of90° C. with respect to a polyimide film and a glossy surface of a copperfoil. Soldering heat resistance test of the photosensitive film showedthat the photosensitive film got a “pass” until 360° C. under the NormalCondition, and until 350° C. under the Moisture Condition. Moreover,flame resistance test of the photosensitive film showed that thephotosensitive film was extinguished in 4.5 seconds on average and got a“pass”. Further, flexibility test of the photosensitive film showed thatutterly no crack was caused in the photosensitive film, thus thephotosensitive film got a “pass”. Development test of the photosensitivefilm showed that a hole of a square shape sized 100 μm×100 μm wasdeveloped successfully, and the photosensitive film got a “pass”.

Example 18

[0644] <Synthesis of N,N′-Bis(Acryloyloxy)-Benzophenon-3,4,3′,4′-Tetracarboxylic Imide>

[0645] Into a 100 ml flask, a solution prepared by dissolving 64.45 g(0.2 mol) of benzophenone-benzophenone-3,4,3′,4′-tetracarboxylicanhydride (BTDA) in 30 g of DMF was poured. 16 ml (0.26 mol) ofhydroxylamine (50% aqueous solution) was dropped, at a room temperature,in the solution being stirred. After the dropping, the solution wasgradually heated up, and reacted at 100° C. for one hour. After thereaction, hydrochloric acid aqueous solution of 4 mol/L (4 N) was addedinto a reaction liquid, which was thereby acidified. A target substancewas extracted with chloroform from a reaction mixture thus prepared,thereby separating an organic layer therefrom. The organic layer wasdried with anhydrous magnesium sulfate. Then, chloroform was removedfrom the organic layer. Thereby, 65.51 g (yield 93%) ofN,N′-bis(hydroxyethyl)-benzophenone-3,4,3′,4′-tetracarboxylic imide(viscous material of transparent and colorless).

[0646] Next, 35.22 g (0.10 mol) ofN,N′-bis(hydroxyethyl)-benzophenone-3,4,3′,4′-tetracarboxylic imide, 30ml (0.22 mol) of triethylamine, and 100 ml of 1,2-dichloroethane werepoured in a 100 ml flask. Then, 28.8 ml (0.360 mol) of acrylyl chloridewas slowly dropped therein at a room temperature under nitrogen withstirring. After the dropping, a mixture thus prepared was reacted forone hour at a room temperature. A reaction mixture was washed with waterso as to separate an organic layer therefrom. Then, the organic layerwas washed with a 5% sodium hydrogen carbonate aqueous solution. Theorganic layer separated from the 5% sodium hydrogen carbonate aqueoussolution was dried with magnesium sulfate, and then a solvent wasremoved from the organic layer. 35.66 g ofN,N′-bis(acryloyloxy)-benzophenone-3,4,3′,4′-tetracarboxylic imide(viscous liquid of dark yellow color) was thereby obtained.N,N′-bis(acryloyloxy)-benzophenone-3,4,3′,4′-tetracarboxylic imide isrepresented by the following formula (123):

[0647] <Preparation of Photosensitive Film>A photosensitive resincomposition was prepared by mixing the same component in the same manneras in Example 11, except thatN,N′-bis(acryloyloxy)-benzophenone-3,4,3′,4′-tetracarboxylic imide thussynthesized above was used as an imide acrylate. Then, a photosensitivefilm was prepared in the fashion mentioned above.

[0648] The photosensitive film had a compression-bondable temperature of110° C. with respect to a polyimide film and a glossy surface of acopper foil. Soldering heat resistance test of the photosensitive filmshowed that the photosensitive film got a “pass” until 360° C. under theNormal Condition, and until 350° C. under the Moisture Condition.Moreover, flame resistance test of the photosensitive film showed thatthe photosensitive film was extinguished in 4.5 seconds on average andgot a “pass”. Further, flexibility test of the photosensitive filmshowed that utterly no crack was caused in the photosensitive film, thusthe photosensitive film got a “pass”. Development test of thephotosensitive film showed that a hole of a square shape sized 100μm×100 μm was developed successfully, and the photosensitive film got a“pass”.

Comparative Example 4

[0649] A photosensitive resin composition was prepared by mixing thesame components in the same manner as in Example 11, except that acopolymer synthesized by copolymerizing methylmethacrylate,n-butylmethacrylate, 2-ethylhexylacrylate, and methacrylic acid, in acopolymerization ratio (by weight) of 55:8:15:22 was used instead of thesoluble polyimide. Then, a photosensitive film was prepared by themethod described above.

[0650] The photosensitive film had a compression-bondable temperature of80° C. with respect to a polyimide film and a glossy surface of a copperfoil. Soldering heat resistance test of the photosensitive film showedthat the photosensitive film got a “pass” until 320° C. under the NormalCondition, and until 310° C. under the Moisture Condition. However,flame resistance test of the photosensitive film showed that thephotosensitive film was not extinguished within 10 seconds and wasburned up with a large flame up to positions of clamps. Thus, thephotosensitive film got a “fail” in the flame resistance test. Further,flexibility test of the photosensitive film showed that utterly no crackwas caused in the photosensitive film, thus the photosensitive film gota “pass”. Development test of the photosensitive film showed that a holeof a square shape sized 100 μm×100 μm was developed successfully, andthe photosensitive film got a “pass”.

[0651] As described above, a photosensitive film in which the polymerthat was not the soluble polyimide was poor in the flame resistance.

Comparative Example 5

[0652] A photosensitive resin composition was prepared by mixing thecomponents in the following amounts. Then, a photosensitive film wasprepared, in which a soluble polyimide and an imide(meth)acrylatecompound were not used. A copolymer synthesized by copolymerizing 70parts methylmethacrylate, n-butylmethacrylate, by weight,2-ethylhexylacrylate, and methacrylic acid, in a copolymerization ratio(by weight) of 55:8:15:22: Bisphenol A EO modified (m + n ≈ 30)diacrylate (NK 10 parts ester A-BPE-30, made by Shin-Nakamura ChemicalCo., by weight, Ltd.): Bisphenol A EO modified (m + n ≈ 4) diacrylate 20parts (allonix M-211B, made by Toagosei Co., Ltd.): by weight,Bis(2,4,6-trimethylbenzoil)phenylphosphineoxide 1 part (irgacure 819made by Ciba Specialty Chemicals K.K.): by weight.

[0653] The photosensitive film had a compression-bondable temperature of100° C. with respect to a polyimide film and a glossy surface of acopper foil. Soldering heat resistance test of the photosensitive filmshowed that the photosensitive film got a “pass” until 270° C. under theNormal Condition, and until 250° C. under the Moisture Condition.However, flame resistance test of the photosensitive film showed thatthe photosensitive film was not extinguished within 10 seconds and wasburned up with a large flame up to positions of clamps. Thus, thephotosensitive film got a “fail” in the flame resistance test. Further,flexibility test of the photosensitive film showed that cracks werecaused in a cover lay film both by folding the photosensitive film witha cover lay film surface facing outward, and by folding thephotosensitive film with a cover lay film surface facing inward. Thusthe photosensitive film got a “fail” in the flexibility test.Development test of the photosensitive film showed that a hole of asquare shape sized 100 μm×100 μm was developed successfully, and thephotosensitive film got a “pass”.

[0654] As described above, the photosensitive film in which the solublepolyimide and imide acrylate were not used was poor in heat resistance,flame resistance, and flexibility attained after being cured.

Comparative Example 6

[0655] A photosensitive resin composition was prepared by mixing thesame components in the same method as in Example 13, except that acopolymer synthesized by copolymerizing methylmethacrylate,n-butylmethacrylate, 2-ethylhexylacrylate, and methacrylic acid in acopolymerization ratio (by weight) of 55:8:15:22 was used as a solublepolyimide. Then, a photosensitive film was prepared by the methoddescribed above.

[0656] The photosensitive film had a compression-bondable temperature of80° C. with respect to a polyimide film and a glossy surface of a copperfoil. Soldering heat resistance test of the photosensitive film showedthat the photosensitive film got a “pass” until 280° C. under the NormalCondition, and until 270° C. under the Moisture Condition. However,flame resistance test of the photosensitive film showed that thephotosensitive film was not extinguished within 10 seconds and wasburned up with a large flame up to positions of clamps. Thus, thephotosensitive film got a “fail” in the flame resistance test. Further,flexibility test of the photosensitive film showed that utterly no crackwas caused in the photosensitive film, thus the photosensitive film gota “pass”. Development test of the photosensitive film showed that a holeof a square shape sized 100 μm×100 μm was developed successfully, andthe photosensitive film got a “pass”.

[0657] As described above, poor in the heat resistance and the flameresistance was the photosensitive film in which the copolymer that wasnot a polyimide was used.

[0658] [Preparation of Photosensitive Film]

[0659] In Examples 19 to 24 and Comparative Examples 7 to 10,photosensitive films were prepared in a manner basically same as in theabove-mentioned <Preparation of Photosensitive Film>. As to 10% weightloss temperature of phosphorous compound used as (D) fire retardants,the photosensitive films were evaluated as follows.

[0660] <10% Weight Loss Temperature of Phosphorous Compound>

[0661] By using a differential scanning calorimeter (TG/DTA 220 made bySeiko Corp.), a temperature range from 20° C. to 600° C. was measured ata temperature elevation rate of 20° C./min in a presence of air. Atemperature at which a weight of a sample was reduced by 10% wasdetermined as a 10% weight loss temperature (10% mass reductiontemperature).

Example 19

[0662] As raw materials of a polyimide, ESDA, BAPS-M, MBAA, and KF-8010mentioned above, were used. As solvents, N,N′-dimethylformamide (DMF)and dioxolane were used.

[0663] <Synthesis of Polyimide>

[0664] Into a 500 ml separable flask provided with a stirring apparatus,17.3 g (0.030 mol) of ESDA, and 30 g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. Next, into the solutionthus prepared, 5.15 g (0.018 mol) of diamine MBAA dissolved in 9 g ofDMF was added. Then, the solution was vigorously stirred. After thesolution was thoroughly mixed, 7.47 g (0.009 mol) of KF-8010 (made byShin-Etsu Silicone) was added as siloxanediamine. Then, the solution wasvigorously stirred. After the solution was thoroughly mixed, 1.29 g(0.003 mol) of BAPS-M was finally added. Then, the solution wasvigorously stirred for 1 hour. A polyamide solution thus prepared wastransferred into a vat coated with a fluorine-based resin. The polyamidesolution in the vat was vacuum-dried at 200° C. for 2 hours under apressure of 660 Pa by using a vacuum oven. Thereby, 26.40 g of a solublepolyimide was synthesized. 50 g or more of the polyimide was dissolvedinto 100 g of tetrahydrofuran (at 20° C.). Because 50 g or more wasdissolved, the polyimide came under a soluble polyimide defined in thepresent invention.

[0665] <Preparation of Photosensitive Film>

[0666] 15 g of the soluble polyimide was dissolved into 35 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%. A photosensitive resincomposition was prepared by adding the following components in thefollowing amounts. The soluble (by solid content by weight): 60 parts byweight, Bisphenol A EO modified (m + n ≈ 30) diacrylate (NK 5 partsester A-BPE-30 made by Shin-Nakamura Chemical Co., by weight, Ltd.):Bisphenol A EO modified (m + n ≈ 4) diacrylate 5 parts (allonix M-221B,made by Toagosei Co., Ltd.): by weight, Diphenoxy phosphazen (degree of30 parts polymerization = 3&4, SP-134, made by Otsuka Chemical byweight, Co., Ltd.) (having 10% weight loss temperature of 370° C.):Bis(2,4,6-trimethylbenzoil)phenylphosphineoxide 1 part (irgacure 819made by Ciba Specialty Chemicals K.K.): by weight.

[0667] A photosensitive film in the B stage condition was prepared byapplying the photosensitive resin composition on a PET film in themanner mentioned above. Further, a protective film was laminatedthereon, thereby obtaining a three-layer sheet (laminate).

[0668] The photosensitive film had a compression-bondable temperature of110° C. with respect to a polyimide film and a glossy surface of acopper foil. Flame resistance test of the photosensitive film showedthat the photosensitive film was extinguished in 2.5 seconds on average.Thus, the photosensitive film got a “pass” in the flame resistance test.Soldering heat resistance test of the photosensitive film showed thatthe photosensitive film got a “pass” until 360° C. under the NormalCondition, and until 350° C. under the Moisture Condition. Developmenttest of the photosensitive film showed that a hole of a square shapesized 100 μm×100 μm was developed successfully, and the photosensitivefilm got a “pass”.

Example 20

[0669] <Synthesis of Modified Polyimide>

[0670] 20.8 g (0.020 mol) of the polyimide synthesized in Example 19 wasdissolved in 80 g of dioxolane. Then, 0.030 g of 4-methoxy phenol wasadded therein, and dissolved by moderately heating by using an oil bathof 60° C. Into a solution thus prepared, 3.75 g (0.0264 mol) of glycidylmethacrylate dissolved in 5 g of dioxolane was added. Further, as acatalyst, 0.01 g of triethylamine was added in the solution. Then, thesolution was heated at 60° C. for 6 hours with stirring. In this way, amodified polyimide was synthesized.

[0671] <Preparation of Photosensitive Film>

[0672] A photosensitive resin composition was prepared by mixing thefollowing components in the following amounts. Then, a photosensitivefilm/three-layer sheet was prepared in the manner mentioned above. Themodified polyimide (by solid content by 50 parts weight): by weight,Bisphenol A EO modified (m + n ≈ 30) diacrylate (NK 5 parts esterA-BPE-30, made by Shin-Nakamura Chemical Co., by weight, Ltd.):Bisphenol A EO modified (m + n ≈ 4) diacrylate 15 parts (allonix M-211B,made by Toagosei Co., Ltd.): by weight, Diphenoxy phosphazen (degree ofpolymerization = 30 parts 3 to 10, SP-100, made by Otsuka Chemical Co.,Ltd.) by weight, (having 10% weight loss temperature of 370° C.):Bis(2,4,6-trimethylbenzoil)phenylphosphineoxide 1 part (irgacure 819made by Ciba Specialty Chemicals K.K.): by weight.

[0673] The photosensitive film had a compression-bondable temperature of80° C. with respect to a polyimide film and a glossy surface of a copperfoil. Flame resistance test of the photosensitive cover lay film showedthat the photosensitive cover lay film was extinguished in 4.0 secondson average. Thus, the photosensitive film got a “pass” in the flameresistance test. Soldering heat resistance test of the photosensitivefilm showed that the photosensitive film got a “pass” until 360° C.under the Normal Condition, and until 350° C. under the MoistureCondition. Development test of the photosensitive film showed that ahole of a square shape sized 100 μm×100 μm was developed successfully,and the photosensitive film got a “pass”.

Example 21

[0674] As a raw material of a polyimide,3,3′,4,4′-biphenylethertetracarboxylic anhydride (ODPA) was used. Asdiamines, BAPS-M, MBAA, and KF-8010 were used. As solvents,N,N′-dimethylformamide (DMF) and a dioxolane.

[0675] <Synthesis of Polyimide>

[0676] Into a 500 ml separable flask provided with a stirring apparatus,9.31 g (0.030 mol) of ODPA, and 30 g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. Next, into the solutionthus prepared, a solution prepared by dissolving 4.29 g (0.015 mol) ofMBAA, made by Wakayama Seika Kogyo Ltd., in 10 g of DMF was added as adiamine. Then, the solution was vigorously stirred. After the solutionwas thoroughly mixed, 7.47 g (0.009 mol) of KF-8010 (made by Shin-EtsuSilicone) was added as siloxanediamine. Then, the solution wasvigorously stirred. After the solution was thoroughly mixed, 2.58 g(0.006 mol) of BAPS-M was finally added. Then, the solution wasvigorously stirred for 1 hour. A polyamide solution thus prepared wastransferred into a vat coated with a fluorine-based resin. The polyamidesolution in the vat was vacuum-dried at 200° C. for 2 hours under apressure of 660 Pa by using a vacuum oven. Thereby, 21.28 g of a solublepolyimide was synthesized.

[0677] 50 g or more of the polyimide was dissolved into 100 g oftetrahydrofuran (at 20° C.). Because 50 g or more was dissolved, thepolyimide came under a soluble polyimide defined in the presentinvention.

[0678] <Preparation of Photosensitive Film>

[0679] 21 g of the soluble polyimide was dissolved into 49 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%. Then, a photosensitive resincomposition was prepared by adding the following compounds in thefollowing amounts, and a photosensitive film/three-layer sheet wasprepared by the method described above. The soluble polyimide (by solidcontent by weight): 55 parts by weight, Bisphenol A EO modified (m + n ≈30) diacrylate (NK 5 parts ester A-BPE-30 made by Shin-Nakamura ChemicalCo., by weight, Ltd.): Bisphenol A EO modified (m + n ≈ 4) diacrylate 10parts (allonix M-211B made by Toagosei Co., Ltd.): by weight,Bis(2-vinylphenoxy) phosphazen (degree of 30 parts polymerization = 3)(10% weight loss by weight, temperature = 380° C.):4,4′-bis(diethylamino)benzophenone: 1 part by weight,3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone: 1 part by weight.

[0680] The photosensitive film had a compression-bondable temperature of90° C. with respect to a polyimide film and a glossy surface of a copperfoil. Flame resistance test of the photosensitive film showed that thephotosensitive film was extinguished in 2.0 seconds on average. Thus,the photosensitive film got a “pass” in the flame resistance test.Soldering heat resistance test of the photosensitive film showed thatthe photosensitive film got a “pass” until 360° C. under the NormalCondition, and until 350° C. under the Moisture Condition. Developmenttest of the photosensitive film showed that a hole of a square shapesized 100 μm×100 μm was developed successfully, and the photosensitivefilm got a “pass”.

Example 22

[0681] As a raw material of a polyimide,3,3′,4,4′-biphenylsulfonetetracarboxylic anhydride (DSDA) was used. Asdiamines, BAPS-M, MBAA, and KF-8010 mentioned above were used. Assolvents, N,N′-dimethylformamide (DMF) and dioxolane were used.

[0682] <Synthesis of Polyimide>

[0683] Into a 500 ml separable flask provided with a stirring apparatus,10.75 g (0.030 mol) of DSDA, and 30 g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. Next, into the solutionthus prepared, 4.29 g (0.015 mol) of diamine MBAA (made by WakayamaSeika Kogyo Ltd.) dissolved in 10 g of DMF was added. Then, the solutionwas vigorously stirred. After the solution was thoroughly mixed, 7.47 g(0.009 mol) of KF-8010 (made by Shin-Etsu Silicone) was added assiloxanediamine. Then, the solution was vigorously stirred. After thesolution was thoroughly mixed, 2.58 g (0.006 mol) of BAPS-M was finallyadded. Then, the solution was vigorously stirred for 1 hour. A polyamidesolution thus prepared was transferred into a vat coated with afluorine-based resin. The polyamide solution in the vat was vacuum-driedat 200° C. for 2 hours under a pressure of 660 Pa by using a vacuumoven. Thereby, 22.57 g of a soluble polyimide was obtained.

[0684] 50 g or more of the polyimide was dissolved into 100 g oftetrahydrofuran (at 20° C.). Because 50 g or more was dissolved, thepolyimide came under a soluble polyimide defined in the presentinvention.

[0685] <Preparation of Photosensitive Film>

[0686] 21 g of the soluble polyimide was dissolved into 49 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%. A photosensitive resincomposition was prepared by adding the following components in thefollowing amounts, and a photosensitive film/three-layer sheet wasprepared by the method described above. The soluble polyimide (by solidcontent by weight): 40 parts by weight. Bisphenol A EO modified (m + n ≈30) diacrylate (NK 5 parts ester A-BPE-30 made by Shin-Nakamura ChemicalCo., by weight, Ltd.): Bisphenol A EO modified (m + n ≈ 4) diacrylate 5parts (allonix M-211B, made by Toagosei Co., Ltd.): by weight,Isocyanuric acid EO modified diacrylate (allonix 5 parts M-215, made byToagosei Co., Ltd.): by weight, Polyphosphoric melamine (PMP-100, madeby 25 parts Nissan Chemical Industries Ltd.) (having a 10% weight byweight, loss temperature of 380° C.):4,4′-bis(diethylamino)benzophenone: 1 part by weight,3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone: 1 part by weight.

[0687] The photosensitive film had a compression-bondable temperature of130° C. with respect to a polyimide film and a glossy surface of acopper foil. Flame resistance test of the photosensitive film showedthat the photosensitive film was extinguished in 4.0 seconds on average.Thus, the photosensitive film got a “pass” in the flame resistance test.Soldering heat resistance test of the photosensitive film showed thatthe photosensitive film got a “pass” until 360° C. under the NormalCondition, and until 350° C. under the Moisture Condition. Developmenttest of the photosensitive film showed that a hole of a square shapesized 100 μm×100 μm was developed successfully, and the photosensitivefilm got a “pass”.

Example 23

[0688] A photosensitive resin composition was prepared by mixing thesame components in the same manner as in Example 20, except thatpolyphosphoric ammonium (sumisave PM made by Sumitomo Chemical Co.,Ltd.)

[0689] (having a 10% weight loss temperature of 375° C. was used insteadof diphenoxyphosphazen. Then, a photosensitive film/three-layer sheetwas prepared by the method mentioned above.

[0690] The photosensitive film had a compression-bondable temperature of100° C. with respect to a polyimide film and a glossy surface of acopper foil. Flame resistance test of the photosensitive film showedthat the photosensitive film was extinguished in 2.8 seconds on average.Thus, the photosensitive film got a “pass” in the flame resistance test.Soldering heat resistance test of the photosensitive film showed thatthe photosensitive film got a “pass” until 360° C. under the NormalCondition, and until 350° C. under the Moisture Condition. Developmenttest of the photosensitive film showed that a hole of a square shapesized 100 μm×100 μm was developed successfully, and the photosensitivefilm got a “pass”.

Example 24

[0691] The above-mentioned BSAA, s-BPDA, BAPS-M,2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and KF-8010 wereused as raw materials of a polyimide. As solvents,N,N′-dimethylformamide (DMF) and dioxolane were used.

[0692] <Synthesis of Polyimide>

[0693] Into a 500 ml separable flask provided with a stirring apparatus,26.02g (0.050 mol) of BSAA, and 30g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. After they weredissolved, 14.71 g (0.050 mol) of s-BPDA and 20 g of DMF were addedthereto. Then, a solution was vigorously stirred again. Then, asdiamines, 18.31 g (0.050 mol) of2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane dissolved in 30 g ofDMF was added, and the solution was vigorously stirred. After thesolution was thoroughly mixed, 24.90 g (0.030 mol) of KF-8010 (made byShin-Etsu Silicone) was added as siloxanediamine. Then, the solution wasvigorously stirred. After the solution was thoroughly mixed, 8.61 g(0.020 mol) of BAPS-M was finally added. Then, the solution wasvigorously stirred for 1 hour. A polyamide solution thus prepared wastransferred into a vat coated with a fluorine-based resin. The polyamidesolution in the vat was vacuum-dried at 200° C. for 2 hours under apressure of 660 Pa by using a vacuum oven. Thereby, 83.5 g of a solublepolyimide was obtained.

[0694] 50 g or more of the polyimide was dissolved into 100 g oftetrahydrofuran. Because 50 g or more was dissolved, the polyimide was asoluble polyimide defined in the present invention.

[0695] <Preparation of Photosensitive Film>

[0696] 30 g of the soluble polyimide was dissolved into 70 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%. Then, a photosensitive resincomposition was prepared by adding the following components in the samemanner as in Example 19, except that the above-mentioned solublepolyimide was used, instead of the polyimide used in Example 19. Then, aphotosensitive film/three-layer sheet was prepared in theabove-mentioned method.

[0697] The photosensitive film had a compression-bondable temperature of100° C. with respect to a polyimide film and a glossy surface of acopper foil. Flame resistance test of the photosensitive film showedthat the photosensitive film was extinguished in 4.0 seconds on average.Thus, the photosensitive film got a “pass” in the flame resistance test.Soldering heat resistance test of the photosensitive film showed thatthe photosensitive film got a “pass” until 360° C. under the NormalCondition, and until 350° C. under the Moisture Condition. Developmenttest of the photosensitive film showed that a hole of a square shapesized 100 μm×100 μm was developed successfully, and the photosensitivefilm got a “pass”.

Comparative Example 7

[0698] A photosensitive resin composition was prepared by mixing thesame components in the same manner as in Example 19, except that EOmodified tribromophenylacrylate (BR-31 made by Dai-Ichi Kogyo SeiyakuCo., Ltd.) was used, instead of diphenoxy phosphazen. Then, aphotosensitive film/three-layer sheet was prepared by the methodmentioned above.

[0699] The photosensitive film had a compression-bondable temperature of120° C. with respect to a polyimide film and a glossy surface of acopper foil. Flame resistance test of the photosensitive film showedthat the photosensitive film was extinguished in 4.0 seconds on average.Thus, the photosensitive film got a “pass” in the flame resistance test.Soldering heat resistance test of the photosensitive film showed thatthe photosensitive film got a “pass” until 360° C. under the NormalCondition, and until 350° C. under the Moisture Condition. Developmenttest of the photosensitive film showed that a hole of a square shapesized 100 μm×100 μm was developed successfully, and the photosensitivefilm got a “pass”. A hole of a square shape sized 100 μm×100 μm wasdeveloped successfully, and the photosensitive film got a “pass”.

[0700] However, because a halogen compound is used therein, combustionof the photosensitive film would be possiblly accompanied withgeneration of a poisonous gas of halogen type.

Comparative Example 8

[0701] A photosensitive resin composition was prepared by mixing thesame component in the same manner as in Example 19, except that acopolymer synthesized by copolymerizing methylmethacrylate,n-butylmethacrylate, 2-ethylhexylacrylate, and methacrylic acid in acopolymerization ratio (by weight) of 55:8:15:22 was used instead of thepolyimide of Example 19. Then, a photosensitive film/three-layer sheetwas prepared by the method mentioned above.

[0702] The photosensitive film had a compression-bondable temperature of80° C. with respect to a polyimide film and a glossy surface of a copperfoil. Flame resistance test of the photosensitive film showed that thephotosensitive film was not extinguished within 10 seconds and wasburned up with a large flame up to positions of clamps. Thus, thephotosensitive film got a “fail” in the flame resistance test.

[0703] As described above, a photosensitive film in which a copolymerthat is not a polyimide is used is poor in flame resistance even if aphosphazen compound is used.

Comparative Example 9

[0704] A photosensitive resin composition was prepared by mixing thesame component in the same manner as in Example 22, except that acopolymer synthesized by copolymerizing methylmethacrylate,n-butylmethacrylate, 2-ethylhexylacrylate, and methacrylic acid in acopolymerization ratio (by weight) of 55:8:15:22 was used instead of thepolyimide of Example 22. Then, a photosensitive film/three-layer sheetwas prepared by the method mentioned above.

[0705] The photosensitive film had a compression-bondable temperature of80° C. with respect to a polyimide film and a glossy surface of a copperfoil. Flame resistance test of the photosensitive film showed that thephotosensitive film was not extinguished within 10 seconds and wasburned up with a large flame up to positions of clamps. Thus, thephotosensitive film got a “fail” in the flame resistance test.

[0706] As described above, poor in flame resistance is a photosensitivefilm in which a copolymer that is not a polyimide is used, even if apolyphosphoric melamine compound is used therein.

Comparative Example 10

[0707] A photosensitive resin composition was prepared by mixing thesame component in the same manner as in Example 22, except that acopolymer synthesized by copolymerizing methylmethacrylate,n-butylmethacrylate, 2-ethylhexylacrylate, and methacrylic acid in acopolymerization ratio (by weight) of 55:8:15:22 was used instead of thepolyimide of Example 22, and that EO modified tribromophenyl acrylate(BR-31 made by Dai-Ichi Kogyo Seiyaku Co., Ltd.) instead of diphenoxyphosphazen. Then, a photosensitive film/three-layer sheet was preparedby the method mentioned above.

[0708] The photosensitive film had a compression-bondable temperature of90° C. with respect to a polyimide film and a glossy surface of a copperfoil. Flame resistance test of the photosensitive film showed that thephotosensitive film was extinguished in 8.0 seconds on average. Thus,the photosensitive film got a “fail” in the flame resistance test.

[0709] As shown above, the photosensitive film in which a copolymer thatis not a polyimide is poor in flame resistance even if a bromine-basedfire retardant is used. Further, combustion of the photosensitive filmwould be possibly accompanied with generation of a poisonous gas ofhalogen type.

[0710] [Evaluation of Property of Photosensitive Film]

[0711] In the following Examples 25 to 28, evaluation in soldering heatresistance was carried out basically in the same manner as in the above<Soldering Heat Resistance>. However, a photosensitive film surface waslaminated on a glossy surface of an electrolysis copper foil (aftersoft-etching) by applying a temperature of 100° C. and a force of 75000Pa·m.

Example 25

[0712] As raw materials of a polyimide, ESDA, BAPS-M, MBAA, and KF-8010mentioned above were used. As solvents, N,N′-dimethylformamide (DMF) anddioxolane were used.

[0713] <Synthesis of Polyimide>

[0714] Into a 500 ml separable flask provided with a stirring apparatus,17.3 g (0.030 mol) of ESDA, and 30 g of DMF were poured, so as toprepare a DMF varnish of ESDA. Then, into the DMF varnish, 5.15 g (0.018mol) of diamine MBAA (made by Wakayama Seika Kogyo Ltd.) dissolved in 9g of DMF was added. Then, a solution thus prepared was vigorouslystirred. After the solution was thoroughly mixed, 7.47 g (0.009 mol) ofKF-8010 (made by Shin-Etsu Silicone) was added therein as asiloxanediamine. Then, the solution was vigorously stirred. After thesolution was thoroughly mixed, 1.29 g (0.003 mol) of BAPS-M was finallyadded therein. Then, the solution was vigorously stirred for one hour. Apolyimide solution thus prepared was transferred into a vat coated witha fluorine-based resin. The polyamide solution in the vat wasvacuum-dried at 200° C. for 2 hours under a pressure of 660 Pa by usinga vacuum oven. Thereby, 26.40 g of a polyimide was obtained.

[0715] 50 g or more of the polyimide was dissolved into 100 g oftetrahydrofuran (at 20° C.). Because 50 g or more was dissolved, thepolyimide came under a soluble polyimide defined in the presentinvention.

[0716] 15 g of the soluble polyimide was dissolved into 35 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%. A photosensitive resincomposition was prepared by adding the following components in thefollowing amounts. Then, the photosensitive resin composition wasapplied on a PET film, so as to prepare a photosensitive film in the Bstage condition. A protective film was further laminated on thephotosensitive film, whereby a photosensitive film/three-layer sheet wasprepared. The soluble polyimide (by solid content by weight): 60 partsby weight, Bisphenol A EO modified (recurring units of 5 partsethyleneoxide modified sites; m + n ≈ 30) by weight, diacrylate (NKester A-BPE-30 made by Shin-Nakamura Chemical Co., Ltd.): Bisphenol A EOmodified (the same as above; 5 parts m + n ≈ 4) diacrylate (allonixM-211B made by by weight, Toagosei Co., Ltd.): Branched methylphenylsiloxane compound 30 parts (KR-211 made by Shin-Etsu Silicone)(phenylcontent: by weight, about 70%):Bis(2,4,6-trimethylbenzoil)phenylphosphineoxide 1 part (irgacure 819made by Ciba Specialty Chemicals K.K.): by weight.

[0717] The photosensitive film had a compression-bondable temperature of100° C. with respect to a polyimide film and a glossy surface of acopper foil. Flame resistance test of the photosensitive film showedthat the photosensitive film was extinguished in 4.0 seconds on average.Thus, the photosensitive film got a “pass” in the flame resistance test.Soldering heat resistance test of the photosensitive film showed thatthe photosensitive film got a “pass” until 360° C. under the NormalCondition, and until 350° C. under the Moisture Condition. Developmenttest of the photosensitive film showed that a hole of a square shapesized 100 μm×100 μm was developed successfully, and the photosensitivefilm got a “pass”.

Example 26

[0718] <Synthesis of Modified Polyimide>

[0719] 20.8 g (0.020 mol) of the polyimide prepared in Example 25 wasdissolved in 80 g of dioxolane. Into a solution thus prepared, 0.030 gof 4-methoxy phenol was added and dissolved by moderately heating byusing an oil bath of 60° C. Into the solution, 3.75 g (0.0264 mol) ofglycidyl methacrylate dissolved in 5 g of dioxolane was added. As acatalyst, 0.01 g of triethylamine was further added therein. Then, thesolution was stirred at 60° C. for 6 hours. In this way, a modifiedpolyimide was synthesized.

[0720] <Preparation of Photosensitive Film>

[0721] A photosensitive resin composition was prepared by mixing thefollowing components in the following amounts. Then, a photosensitivefilm/three-layer sheet was prepared in the manner mentioned above. Themodified polyimide (by solid content by 50 parts weight): by weight,Bisphenol A EO modified (m + n ≈ 30) diacrylate 5 parts (NK esterA-BPE-30, made by Shin-Nakamura Chemical Co., by weight, Ltd.):Bisphenol A EO modified (m + n ≈ 4) diacrylate 15 parts (allonix M-211B,made by Toagosei Co., Ltd.): by weight, Branched methyl phenyl siloxanecompound having 30 parts a vinyl group in a side chain (KR-215 made byShin-Etsu by weight, Chemical Co., Ltd.) (phenyl content: about 70%):Bis(2,4,6-trimethylbenzoil)phenylphosphineoxide 1 part (irgacure 819made by Ciba Specialty Chemicals K.K.): by weight.

[0722] The photosensitive film had a compression-bondable temperature of110° C. with respect to a polyimide film and a glossy surface of acopper foil. Flame resistance test of the photosensitive cover lay filmshowed that the photosensitive cover lay film was extinguished in 3.5seconds on average. Thus, the photosensitive film got a “pass” in theflame resistance test. Soldering heat resistance test of thephotosensitive film showed that the photosensitive film got a “pass”until 360° C. under the Normal Condition, and until 350° C. under theMoisture Condition. Development test of the photosensitive film showedthat a hole of a square shape sized 100 μm×100 μm was developedsuccessfully, and the photosensitive film got a “pass”.

Example 27

[0723] As raw materials of a polyimide, ODPA, BAPS-M, MBAA, and KF-8010mentioned above were used. As solvents, N,N′-dimethylformamide (DMF) anddioxolane were used.

[0724] <Synthesis of Polyimide>

[0725] Into a 500 ml separable flask provided with a stirring apparatus,9.31 g (0.030 mol) of ODPA, and 30 g of DMF were poured, so as toprepare a DMF varnish of ODPA. Then, into the DMF varnish, 4.29 g (0.015mol) of diamine MBAA (made by Wakayama Seika Kogyo Ltd.) dissolved in 10g of DMF was added. Then, a solution thus prepared was vigorouslystirred. After the solution was thoroughly mixed, 7.74 g (0.009 mol) ofKF-8010 (made by Shin-Etsu Silicone) was added therein as asiloxanediamine. Then, the solution was vigorously stirred. After thesolution was thoroughly mixed, 2.58 g (0.006 mol) of BAPS-M was finallyadded therein. Then, the solution was vigorously stirred for one hour. Apolyamide solution thus prepared was transferred into a vat coated witha fluorine-based resin. The polyamide solution in the vat wasvacuum-dried at 200° C. for 2 hours under a pressure of 660 Pa by usinga vacuum oven. Thereby, 21.28 g of a soluble polyimide was obtained.

[0726] 50 g or more of the polyimide was dissolved into 100 g oftetrahydrofuran (at 20° C.). Because 50 g or more was dissolved, thepolyimide came under a soluble polyimide defined in the presentinvention.

[0727] <Preparation of Photosensitive Film>

[0728] 21 g of the soluble polyimide was dissolved into 49 g ofdioxolane, thereby preparing a varnish having a solid content % byweight (Sc) of 30%. A photosensitive resin composition was prepared byadding the following components in the following amounts. Aphotosensitive film/three-layer sheet was prepared in the mannerdescribed above. The soluble polyimide (by solid content by weight): 55parts by weight, Bisphenol A EO modified (m + n ≈ 30) diacrylate 5 parts(NK ester A-BPE-30 made by Shin-Nakamura Chemical Co., by weight, Ltd.):Bisphenol A EO modified (the same as above; 10 parts m + n ≈ 4)diacrylate (allonix M-211B made by by weight, Toagosei Co., Ltd.):Branched methylphenyl siloxane compound (KF-56 30 parts made byShin-Etsu Silicone)(phenyl content: about 25%): by weight,4,4′-bis(diethylamino)benzophenone: 1 part by weight,3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone: 1 part by weight.

[0729] The photosensitive film had a compression-bondable temperature of90° C. with respect to a polyimide film and a glossy surface of a copperfoil. Flame resistance test of the photosensitive film showed that thephotosensitive film was extinguished in 3.0 seconds on average. Thus,the photosensitive film got a “pass” in the flame resistance test.Soldering heat resistance test of the photosensitive film showed thatthe photosensitive film got a “pass” until 360° C. under the NormalCondition, and until 350° C. under the Moisture Condition. Developmenttest of the photosensitive film showed that a hole of a square shapesized 100 μm×100 μm was developed successfully, and the photosensitivefilm got a “pass”.

Example 28

[0730] As raw materials of a polyimide, DSDA, BAPS-M, MBAA, and KF-8010mentioned above were used. As solvents, N,N′-dimethylformamide (DMF) anddioxolane were used.

[0731] <Synthesis of Polyimide>

[0732] Into a 500 ml separable flask provided with a stirring apparatus,10.75 g (0.030 mol) of DSDA, and 30 g of DMF were poured, and dissolvedwith stirring by using the stirring apparatus. Then, 4.29 g (0.015 mol)of diamine MBAA (made by Wakayama Seika Kogyo Ltd.) dissolved in 10 g ofDMF was added thereto. After the solution was thoroughly mixed, 7.47 g(0.009 mol) of KF-8010 (made by Shin-Etsu Silicone) was added assiloxanediamine. Then, the solution was vigorously stirred. After thesolution was thoroughly mixed, 2.58 g (0.006 mol) of BAPS-M was finallyadded. Then, the solution was vigorously stirred for 1 hour. A polyamidesolution thus prepared was transferred into a vat coated with afluorine-based resin. The polyamide solution in the vat was vacuum-driedat 200° C. for 2 hours under a pressure of 660 Pa by using a vacuumoven. Thereby, 22.57 g of a soluble polyimide was obtained.

[0733] 50 g or more of the polyimide was dissolved into 100 g oftetrahydrofuran (at 20° C.). Because 50 g or more was dissolved, thepolyimide came under a soluble polyimide defined in the presentinvention.

[0734] <Preparation of Photosensitive Film>

[0735] 21 g of the soluble polyimide was dissolved into 49 g ofdioxolane, thereby preparing a varnish of a soluble polyimide having asolid content % by weight (Sc) of 30%. Then, a photosensitive resincomposition was prepared by adding the following components in thefollowing amounts. Then, a photosensitive film/three-layer sheet wasprepared in the above-mentioned method. The soluble polyimide (by solidcontent by weight): 50 parts by weight, Bisphenol A EO modified (m + n ≈30) diacrylate 10 parts (NK ester A-BPE-30 made by Shin-NakamuraChemical Co., by weight, Ltd.): Bisphenol A EO modified (m + n ≈ 4)diacrylate 5 parts (allonix M-211B, made by Toagosei Co., Ltd.): byweight, Isocyanuric acid EO modified diacrylate (allonix 5 parts M-215,made by Toagosei Co., Ltd.): by weight, Methylphenyl siloxane compoundhaving a 30 parts branched main chain and a side chain having amethacryl by weight, group (KR-217 made by Shin-Etsu Chemical Co.,Ltd.)(phenyl content: about 40%): 4,4′-bis(diethylamino)benzophenone: 1part by weight, 3,3′,4,4′-tetra(t-butylperoxycaronyl)benzophenone: 1part by weight.

[0736] The photosensitive film had a compression-bondable temperature of130° C. with respect to a polyimide film and a glossy surface of acopper foil. Flame resistance test of the photosensitive cover lay filmshowed that the photosensitive cover lay film was extinguished in 4.0seconds on average. Thus, the photosensitive film got a “pass” in theflame resistance test. Soldering heat resistance test of thephotosensitive film showed that the photosensitive film got a “pass”until 360° C. under the Normal Condition, and until 350° C. under theMoisture Condition. Development test of the photosensitive film showedthat a hole of a square shape sized 100 μm×100 μm was developedsuccessfully, and the photosensitive film got a “pass”.

Comparative Example 11

[0737] A photosensitive resin composition was prepared by mixing thesame components in the same manner as in Example 25, except that aunbranched methylphenyl siloxane compound (HVAC F-5, made by Shin-EtsuChemical Co., Ltd.) (phenyl group content: 62.5%) was used instead ofthe branched methylphenyl siloxane compound. Then, a photosensitivefilm/three-layer sheet was prepared by the method mentioned above.

[0738] The photosensitive film had a compression-bondable temperature of90° C. with respect to a polyimide film and a glossy surface of a copperfoil. Flame resistance test of the photosensitive cover lay film showedthat the photosensitive cover lay film was not extinguished within 10seconds and was burned up with a large flame up to positions of clamps.Thus, the photosensitive film got a “fail” in the flame resistance test.Further, soldering heat resistance test of the photosensitive filmshowed that the photosensitive film got a “pass” until 360° C. under theNormal Condition, and until 350° C. under the Moisture Condition.Development test of the photosensitive film showed that a hole of asquare shape sized 100 μm×100 μm was developed successfully, and thephotosensitive film got a “pass”.

[0739] As shown above, it is impossible to realize flame resistance, ifan unbranched siloxane oligomer is used.

Comparative Example 12

[0740] A photosensitive resin composition was prepared by mixing thesame components in the same manner in Example 25, except that acopolymer synthesized by copolymerizing methylmethacrylate,n-butylmethacrylate, 2-ethylhexylacrylate, and methacrylic acid in acopolymerization ratio (by weight) of 55:8:15:22 was used instead of thepolyimide of Example 25. Then, a photosensitive film/three-layer sheetwas prepared by the method mentioned above.

[0741] The photosensitive film had a compression-bondable temperature of80° C. with respect to a polyimide film and a glossy surface of a copperfoil. Flame resistance test of the photosensitive cover lay film showedthat the photosensitive cover lay film was not extinguished within 10seconds and was burned up with a large flame up to positions of clamps.Thus, the photosensitive film got a “fail” in the flame resistance test.

[0742] As shown above, a photosensitive film in which a copolymer thatis not a polyimide is used is poor in flame resistance even if aphosphazen compound is used therein.

Comparative Example 13

[0743] A photosensitive resin composition was prepared by mixing thesame components in the same manner as in Example 28, except that acopolymer synthesized by copolymerizing methylmethacrylate,n-butylmethacrylate, 2-ethylhexylacrylate, and methacrylic acid in acopolymerization ratio (by weight) of 55:8:15:22 was used instead of thepolyimide of Example 28. Then, a photosensitive film/three-layer sheetwas prepared by the method mentioned above.

[0744] The photosensitive film had a compression-bondable temperature of80° C. with respect to a polyimide film and a glossy surface of a copperfoil. Flame resistance test of the photosensitive film showed that thephotosensitive film was not extinguished within 10 seconds and wasburned up with a large flame up to positions of clamps. Thus, thephotosensitive film got a “fail” in the flame resistance test.

[0745] As shown above, a photosensitive film in which a copolymer thatis not a polyimide is used is poor in flame resistance even ifpolyphosphoric melamine is used therein.

Comparative Example 14

[0746] A photosensitive resin composition was prepared by mixing thesame components in the same manner as in Example 28, except thatmodified dimethyl silicone having an amino group on each terminal(KF-8010 made by Shin-Etsu Silicone) (phenyl content 0%) instead of thebranched methylphenyl siloxane compound. Then, a photosensitivefilm/three-layer sheet was prepared by the method mentioned above.

[0747] The photosensitive film had a compression-bondable temperature of80° C. with respect to a polyimide film and a glossy surface of a copperfoil. Flame resistance test of the photosensitive cover lay film showedthat the photosensitive cover lay film was extinguished in 9.0 secondson average. Thus, the photosensitive film got a “fail” in the flameresistance test.

[0748] As shown above, it is impossible to realize flame resistance inan arrangement in which a siloxane compound having no branched mainchain and no aromatic group is used.

[0749] [Preparation of Photosensitive Film]

[0750] In Examples 29 to 33, and Comparative Examples 15 to 18,photosensitive films were prepared as follows.

[0751] Into a varnish in which a (A) soluble polyimide was dissolved ina mixture solvent of THF and dioxolan so as to attain 30% solid content% (Sc), a (B) (meth)acrylic compound, a (C) photo reaction initiator,and a (D) fire retardant were mixed. A varnish of a photosensitive resincomposition was thereby prepared. The varnish of a photosensitive resincomposition was applied on a supporting film (PET film having athickness of 25 μm) so that the photosensitive resin composition thusapplied would be 25 μm in thickness after dried. Then, thephotosensitive resin composition thus applied on the PET film was driedat 45° C. for 5 minutes and then at 65° C. for 5 minutes, so as toremove an organic solvent. In this way, a photosensitive film in the Bstage condition and a two-layer sheet were obtained.

[0752] Next, on the photosensitive film, a protective film waslaminated, which was a commercially available film: protect (#6221F)film (made by Sekisui Chemical Co., Ltd.; 50 μm in thickness), which isa PE-PE+EVA coextrusion film. With a roll temperature of 40° C. and anip pressure of 1500 Pa·m, the laminating was carried out in such amanner that a (PE+EVA) copolymer film surface was in contact with aphotosensitive film surface. Thereby, a three-layer sheet was prepared.

[0753] [Evaluation of Property of Photosensitive Film]

[0754] In Examples 29 to 31, and Comparative Examples 15 to 18,properties of the photosensitive films were evaluated as follows.

[0755] <Development Property>

[0756] The photosensitive film thus prepared in the above [Preparationof photosensitive film] was placed on an electrolysis copper foil (madeby Mitsui Mining & smelting Co., Ltd., 3EC-VLP 1 ounce) in such a mannerthat a photosensitive resin composition surface of the photosensitivefilm faced a rough surface of the electrolysis copper foil. Whileshielding the photosensitive film from light, laminating was performedby applying a temperature of 100° C. and a force of 20,000 Pa·m. On thePET film of a laminate thus prepared, a photomask was placed. Then, thelaminate was exposed to light of 400 nm by 400 mJ/cm². After the PETfilm of a sample thus prepared was peeled off, the sample was heated at100° C. for 2 minutes, and developed for 3 minuets with 1% potassiumhydroxide aqueous solution (having a liquid temperature of 40° C.). Thephotomask that was placed on a cover film prior to the light exposurehad fine holes of 500 μmφ, 200 μmφ, and 100 μmφ, and lines so arrangedas line/space of 500 μm/500 μm, 200 μm/200 ®m, and 100 μm/100 μm.

[0757] A pattern thus formed by the development was washed withdistilled water, thereby removing a developer. It was judged as “pass”,if at least the hole of 500 μm and the line of 500 μm/500 μm wereformed.

[0758] <Adhesion Strength>

[0759] The photosensitive film thus prepared in the above [Preparationof photosensitive film] was placed on an electrolysis copper foil (madeby Mitsui Mining & smelting Co., Ltd., 3EC-VLP 1 ounce) in such a mannerthat a photosensitive resin composition surface of the photosensitivefilm faced a glossy surface of the electrolysis copper foil. Whileshielding the photosensitive film from light, laminating was performedby applying a temperature of 100° C. and a force of 20,000 Pa·m. Alaminate was exposed to light of 400 nm by 400 mJ/cm², and then heatedat 180° C. for one hour. Peel adhesion strength of the laminate wasperformed, following JIS C 6481: Peel-Off Strength (180°).

Example 29

[0760] As raw materials of a polyimide, ESDA, BAPS-M, MBAA, and KF-8010mentioned above and diamino benzoic acid were used. As solvents,N,N′-dimethylformamide (DMF) and dioxolane were used.

[0761] <Synthesis of Polyimide>

[0762] Into a 500 ml separable flask provided with a stirring apparatus,17.3 g (0.030 mol) of ESDA and 30 g of DMF were poured, and stirred, bythe stirring apparatus, until dissolved. Next, into a solution thusprepared, 5.15 g(0.018 mol)) of diamine MBAA (made by Wakayama SeikaKogyo Ltd) dissolved in 9 g DMF was added. Then, the solution wasvigorously stirred for one hour.

[0763] Further, as a siloxanediamine, 7.47 g (0.009 mol) of KF-8010(made by Shin-Etsu Silicone) was added into the solution. Then, thesolution was stirred for about one hour. Finally, 1.29 g (0.003 mol) ofBAPS-M was added into the solution. Then, the solution was stirredvigorously for one hour. In this way, a polyamide solution was preparedThe polyamide solution was transferred into a vat coated withfluorine-based resin. The polyamide solution in the vat was vacuum-driedat 200° C. for 2 hours under a pressure of 5000 Pa. Thereby, 26.40 g ofa soluble polyimide was obtained.

[0764] 15 g of a soluble polyimide thus prepared was dissolved in 50 gof dioxolane. A varnish of solid content % (Sc) of 30% was therebyprepared.

[0765] <Preparation of Photosensitive Film>

[0766] A photosensitive resin composition was prepared by mixing thefollowing components in the following amounts. Then, a photosensitivefilm in the B stage condition was prepared on a PET film. On thephotosensitive film on the PET film, a protective film was laminatedthereby obtaining a three-layer sheet (laminate). The soluble polyimide(by solid content by weight): 50 parts by weight, Bisphenol A EOmodified (m + n ≈ 30) diacrylate 10 part (NK ester A-BPE-30 made byShin-Nakamura Chemical Co., by weight, Ltd.): Allonix M-215 made byToagosei Co., Ltd. : 40 parts by weight,3,3′4,4′-tetra(t-butylperoxycarbonyl)benzophenone: 1 part by weight,4,4′-diethylaminobenzophenone: 1 part by weight.

Example 30

[0767] <Synthesis of Modified Polyimide>

[0768] 20.8 g (0.020 mol) of the polyimide synthesized in Example 29 wasdissolved in 80 g of dioxolane. Into a solution thus prepared, 0.030 gof 4-methoxy phenol was added and dissolved by moderately heating byusing an oil bath of 60° C. Into a solution thus prepared, 3.75 g(0.0264 mol) of glycidyl methacrylate dissolved in 5 g of dioxolane wasadded, and then 0.01 g of triethylamine was further added as a catalyst.With stirring, a solution thus prepared was heated at 60° C. for 6hours. In this way, a modified polyimide was synthesized.

[0769] <Preparation of Photosensitive Film>

[0770] A photosensitive resin composition was prepared by mixing thefollowing components in the following amounts. Then, a photosensitivefilm in the B stage condition was prepared on a PET film. On thephotosensitive film on the PET film, a protective film was laminatedthereby obtaining a three-layer sheet. The soluble polyimide (by solidcontent by weight): 50 parts by weight, Bisphenol A EO modified (m + n ≈30) diacrylate 10 parts (NK ester A-BPE-30 made by Shin-NakamuraChemical Co., by weight, Ltd.): Allonix M-215 made by Toagosei Co.,Ltd.: 10 parts by weight,3,3′4,4′-tetra(t-butylperoxycarbonyl)benzophenone: 1 part by weight,3,3′-carbonylbis(7-diethylamino)coumarin: 1 part by weight

[0771] Development test of the photosensitive film thus obtained showedthat a fine hole of 100 μmφ and a line of 100 μm/100 μm were developedsuccessfully, and the photosensitive film got a “pass”. Moreover, anadhesive strength of the photosensitive film was 600 Pa·m.

Example 31

[0772] A photosensitive film/three-layer sheet was obtained in the samemanner as in Example 30, except that 1 part by weight ofbis(2,4,6-trimethylbenzoil)phenylphosphineoxide was used instead of 1part by weight of 3,3′4,4′-tetra(t-butylperoxycarbonyl)benzophenone.

[0773] Development test of the photosensitive film thus obtained showedthat a fine hole of 100 μmφ and a line of 100 μm/100 μm were developedsuccessfully, and the photosensitive film got a “pass”. Moreover, anadhesive strength of the photosensitive film was 620 Pa·m.

Comparative Example 15

[0774] A photosensitive film/three-layer sheet was obtained in the samemanner as in Example 30, except that 1 part by weight of benzophenonewas used instead of 1 part by weight of3,3′4,4′-tetra(t-butylperoxycarbonyl)benzophenone.

[0775] Development test of the photosensitive film thus obtained showedthat a fine hole of 500 μmφ and a line of 500 μm/500 μm were developedunsuccessfully, and the photosensitive film got a “fail”. Moreover, anadhesive strength of the photosensitive film was 120 Pa·m.

Comparative Example 16

[0776] A photosensitive film/three-layer sheet was obtained in the samemanner as in Example 30, except that 1 part by weight of methylα-oxobenzeneacetate was used instead of 1 part by weight of3,3′4,4′-tetra(t-butylperoxycarbonyl)benzophenone.

[0777] Development test of the photosensitive film thus obtained showedthat a fine hole of 500 μmφ and a line of 500 μm/500 μm were developedunsuccessfully, and the photosensitive film got a “fail”. Moreover, anadhesive strength of the photosensitive film was 80 Pa·m.

Comparative Example 17

[0778] A photosensitive film/three-layer sheet was obtained in the samemanner as in Example 30, except that 1 part by weight of benzoin wasused instead of 1 part by weight of3,3′4,4′-tetra(t-butylperoxycarbonyl)benzophenone.

[0779] Development test of the photosensitive film thus obtained showedthat a fine hole of 500 μmφ and a line of 500 μm/500 μm were developedunsuccessfully, and the photosensitive film got a “fail”. Moreover, anadhesive strength of the photosensitive film was 50 Pa·m.

Comparative Example 18

[0780] A photosensitive film/three-layer sheet was obtained in the samemanner as in Example 30, except that 1 part by weight of4,4′-diazidochalcone was used instead of 1 part by weight of3,3′4,4′-tetra(t-butylperoxycarbonyl)benzophenone.

[0781] Development test of the photosensitive film thus obtained showedthat a fine hole of 500 μm and a line of 500 μm/500 μm were developedunsuccessfully, and the photosensitive film got a “fail”. Moreover, anadhesive strength of the photosensitive film was 60 Pa·m.

[0782] [Evaluation of Property of Photosensitive Film]

[0783] Properties of photosensitive films in Examples 32 and 33, andComparative Example 19 were carried out as follows.

[0784] <Flame Resistance Test>

[0785] A flame resistance test was carried out as explained below,following flame resistance test standard UL 94 for plastic rawmaterials.

[0786] Firstly, a protective film was peeled off from a three-layersheet. Then, a photosensitive film surface was laminated on a polyimidefilm (made by Kaneka Corp., 25AH film) of 25 μm thickness, by applying atemperature of 100° C. and a force of 20,000 Pa·m while shielding from.Next, a laminate thus formed was exposed to light of 400 nm by 600mJ/cm². Then, a supporting film was peeled off from the laminate thusexposed to light. The laminate from which the supporting film had beenpeeled off was thermally cured by heating for 2 hours in an oven kept at180° C.

[0787] Sample thus prepared was cut into a size of 1.27 cm width x12.7cm length×50 μm thickness (including the thickness of the polyimidefilm). 20 pieces of the cut were thus prepared.

[0788] 10 of the 20 pieces were treated under condition (1) (at 23°C./under 50% relative humidity/for 48 hours), and the other 10 pieceswere treated under condition (2) (at 70° C. for 168 hours. After treatedas such, the pieces was cooled for 4 hours or longer, the pieces beingcontained in a desiccator in which anhydrous calcium was placed.

[0789] The samples thus prepared were vertically held by clipping upperparts thereof by using clamps. Then, the samples were lit up byapproaching, to a lower part thereof, a burner flame for 10 seconds.After 10 seconds the burner flame was moved away. Then, it was measuredhow long it took to extinguish a flame of the sample or inflammation ofthe sample. A sample was judged as “pass” if achieving both that the 10pieces for each condition (conditions (1) and (2)) were extinguished, onaverage (average of 10 pieces), within 5 seconds after the burner flamewas moved away from the samples, and that each of the samples wasself-extinguished by extinguishing the flame or combustion within 10seconds at maximum. A sample was judged as “fail” if any one of thepieces was not extinguished within 10 seconds, or if at least one of thepieces was so combusted that the flame went up to the upper part thereofwhere the clamp was.

[0790] <Development Property>

[0791] A photosensitive film surface of a three-layer sheet from which aprotective film had been peeled off, was placed on an electrolysiscopper foil (made by Mitsui Mining & Smelting Co., Ltd., 3EC-VLP 1ounce) in such a manner that a photosensitive film surface of thephotosensitive film faced a rough surface of the electrolysis copperfoil. While shielding the photosensitive film from light, laminating wasperformed by applying a temperature of 100° C. and a force of 20,000Pa·m. On a supporting film of a laminate thus prepared, a photomask wasplaced. Then, the laminate was exposed to light of 400 nm by 1800mJ/cm². After a supporting film of the sample was peeled off, the samplewas developed for 3 minutes with 1% potassium hydroxide aqueous solution(having a liquid temperature of 40° C.). The photomask that was placedon the photosensitive film prior to the light exposure had fine holes ofa squire shape sized 500 μm×500 μm, of a squire shape sized 200 μm×200μm, and of a squire shape sized 100 μm×100 μm. A pattern thus formed bythe development was washed with distilled water, thereby removing adeveloper. It was judged as “pass”, if at least the hole a squire shapesized 500 μm×500 μm was formed.

[0792] <Line-to-Line Insulating Resistance>

[0793] A line-to-line insulating resistance indicates how electricallyinsulating a photosensitive film is. The larger the resistance, the moreelectrically insulating the photosensitive film.

[0794] A flexible copper-clad laminate (a both-side copper-clad laminateprepared by forming copper foils on both sides of polyimide-based resin)SC 18-25-00WE made by Nippon Steel Chemical Co., Ltd. was etched so asto remove the copper foil on one side thereof. On the thus formedone-side flexible copper-clad laminate, a comb-like shaped pattern ofline/space=100 μm/100 μm as shown in FIG. 2 was formed. Note that, inFIG. 2, for the sake of easy explanation, the pattern is so arrangedthat four lines arranged as line/space=100 μm/100 μm in a comb-likeshape are paired with another four lines similarly arranged in such amanner that each line is alternatively arranged. However, in reality,the pattern is so arranged that ten lines arranged as such are pairedwith ten lines arranged similarly.

[0795] On the pattern of the comb-like shape, a photosensitive film fromwhich a protective film had been peeled off, was laminated, by applyinga temperature of 100° C. and a force of 20,000 Pa·m. Then, a laminatethus formed with the pattern was exposed to light of 400 nm by 1800mJ/cm². Then, the laminate was heated for 2 hours at 180° C. Thereby, asshown in FIG. 2, a photosensitive film 2 was laminated on a flexiblecopper-clad laminate 3.

[0796] The flexible copper-clad laminate 3 on which the photosensitivefilm 2 was laminated was subjected to a condition of 65RH % and 20° C.for 24 hours for moisture conditioning. Then, the line-to-lineinsulating resistance was measured under 65% and 20° C. By using ameasurement apparatus in which a digital super resistor R8340A made byAdvantest Corp. In a sample box (test fixture R12706A made by AdvantestCorp.), an electrode terminal 1 (see FIG. 2) of the flexible copper-cladlaminate 3 thus subjected to humidity modification was fixedly attachedwith a terminal of a test socket. A resistance after 1-minuteapplication of DC 500V after closing the test box was determined as theline-to-line insulating resistance. The higher resistance is morepreferable. Here, if a line-to-line insulating resistance was 10×10¹³ Ωor higher, the photosensitive film was judged as “pass”. Moreover, as toa duration of the resistance, the photosensitive film was judged as“pass” if a resistance of 10¹⁰ Ω or higher was sustained for 500 hours.

[0797] <Soldering Heat Resistance>

[0798] After a protective film was peeled off from a three-layer sheet,a photosensitive film surface thereof was placed on a glossy surface ofan electrolysis copper foil of 35 μm, and then laminated thereon byapplying a temperature of 100° C. and a force of 20,000 Pa·m. Aphotosensitive film of a laminate product thus formed, was exposed, viaa PET film, to light of a wavelength of 400 nm by 1800 mJ/cm². After thePET film was peeled off, the laminate product was heated at 180° C. for2 hours. A laminate sample thus prepared was cut into a square shape of25 mm×25 mm. After subjected to a condition of 35° C. and 85% humidityfor 24 hours for moisture conditioning, The laminate sample of 25 mmx25mm in size was immersed in a melted solder of 300° C. for 1 minute.Then, the laminate sample was observed for whether the sample had adefect such as swelling, peeling-off, and the like. If no defect wasobserved, the protective film was judged as “pass”.

[0799] <Stickiness Strength>

[0800] A photosensitive film of a three-layer sheet from which aprotective film was peeled off, was placed on a smooth surface of anelectrolysis copper-clad foil (3EC-VLP made by Mitsui Mining & SmeltingCo., Ltd., 1 ounce), and laminated thereon by applying a temperature of100° C. and a force of 20,000 Pa·m while shielding light from light.Stickiness strength between the copper foil and the photosensitive filmthus laminated was measured.

[0801] <Adhesion Strength>

[0802] Peel adhesion strength was measured, following JIS C6481:Peel-off Strength (180°). Note that, in measuring the peel adhesionstrength, a width was lcm and stickiness strength between the copperfilm and the photosensitive film was measured.

Example 32

[0803] As raw materials of a polyimide, ESDA, BAPS-M, diaminobenzoidicacid, MBAA, and KE-8010 mentioned above were used. As solvents,N,N′-dimethylformamide (DMF) and dioxolane were used.

[0804] <Synthesis of Polyimide>

[0805] Into a 500 ml separable flask provided with a stirring apparatus,17.3 g (0.030 mol) of ESDA and 30 g of DMF were poured, and stirred, bythe stirring apparatus, until dissolved. Next, into a solution thusprepared, 6.15 g(0.018 mol) of diamine MBAA (made by Wakayama SeikaKogyo Ltd.) dissolved in 9 g DMF was added. Then, the solution wasvigorously stirred for one hour. Further, as a siloxanediamine, 7.47 g(0.009 mol) of KF-8010 (made by Shin-Etsu Silicone) was added into thesolution. Then, the solution was stirred for about one hour. Finally,1.29 g (0.003 mol) of BAPS-M was added into the solution. Then, thesolution was stirred vigorously for one hour. In this way, a polyamidesolution was prepared The polyamide solution was transferred into a vatcoated with fluorine-based resin. The polyamide solution in the vat wasvacuum-dried at 200° C. for 2 hours under a pressure of 660 Pa by usinga vacuum oven. Thereby, 26.40 g of a soluble polyimide was obtained.

[0806] 15 g of the polyimide thus synthesized was dissolved in 50 g ofdioxolane. A varnish of solid content % (Sc) of 30% was therebyprepared.

[0807] <Preparation of Photosensitive Film>

[0808] A photosensitive resin composition was prepared by mixing thefollowing components in the following amounts. Then, the photosensitiveresin composition was applied on a PET film in the method mentionedabove, thereby obtaining a photosensitive film in the B stage condition.Further, a protective film was laminated on the photosensitive film,thereby obtaining a three-layer sheet. The soluble polyimide (by solidcontent by weight): 50 parts by weight, Phenyl siloxane (KF 56 made byShin-Etsu 25 parts Chemical Co., Ltd.): by weight, Phenyl siloxane (KR211 made by Shin-Etsu 5 parts Chemical Co., Ltd.): by weight, BisphenolA EO modified (m + n ≈ 30) diacrylate 10 parts (NK ester A-BPE-30 madeby Shin-Nakamura Chemical Co., by weight, Ltd.): Allonix M-215 made byToagosei Co., Ltd.: 10 parts by weight,3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone: 1 part by weight,4,4′-diethylaminobenzophenone: 1 part by weight.

[0809] Flame resistance test of the photosensitive film showed thatflame was extinguished in 4 seconds on average. Thus, the photosensitivefilm passed the UL94V-0 standard. Moreover, development test of thephotosensitive film showed that a fine hole of a square sized 100 μm×100μm was developed successfully. Thus, the photosensitive film got a“pass” in the development test. Further the photosensitive film had aninsulating resistance of 2.0×10¹⁴ Ω in a normal condition, and anadhesion strength of 500 Pa·m. The photosensitive film got a “pass” insoldering heat resistance.

[0810] Moreover, prepared was a flexible copper-clad laminate on whichthe photosensitive film prepared as in the one used in the measurementof the line-to-line insulating resistance was laminated. A resistance ofthe flexible copper-clad laminate on which the photosensitive film waslaminated was measured by applying a DC 100V in a thermo-hygrostat(PL-2FP, made by Tabai Espec Corp.) having a temperature of 80° C. and ahumidity of 85% RH. A measuring apparatus used here was ion migrationevaluation system AMI-025-PL, made by Tabai Espec Corp. With a migrationevaluation system connected with an electrode terminal 1 shown in FIG.2, a change in measurement values was observed. As a result, aresistance of 10¹⁰ Ω or more was maintained for 1,000 hours, whereby thephotosensitive film got a “pass”.

Example 33

[0811] <Synthesis of Modified Polyimide>

[0812] 20.8 g (0.020 mol) of the polyimide synthesized in Example 32 wasdissolved in 80 g of dioxolane. Then, 0.030 g of 4-methoxy phenol wasadded therein, and dissolved by moderately heat application by using anoil bath of 60° C. Into the solution, a solution prepared by dissolving3.75 g (0.0264 mol) of glycidyl methacrylate in 5 g of dioxolane wasadded. Further, 0.01 g of triethylamine was added as a catalyst in thesolution. Then, the solution was stirred at 60° C. for 6 hours. Therebya modified polyimide was synthesized.

[0813] <Preparation of Photosensitive Film>

[0814] The following components in the following amounts were addedtherein, thereby obtaining a photosensitive resin composition. Then, aphotosensitive film/three-layer sheet was prepared in the same fashionas above. The modified polyimide (by solid content by weight): 50 partsby weight, Phenyl siloxane (KF 56 made by Shin-Etsu 5 parts ChemicalCo., Ltd.): by weight, Phenyl siloxane (KR 211 made by Shin-Etsu 5 partsChemical Co., Ltd.): by weight, Bisphenol A EO modified (m + n ≈ 30)diacrylate 10 parts (NK ester A-BPE-30, made by Shin-Nakamura ChemicalCo., by weight, Ltd.): Allonix M-215 made by Toagosei Co., Ltd.: 10parts by weight, 3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone: 1part by weight, 4,4′-diethylaminobenzophenone: 1 part by weight.

[0815] Flame resistance test of the photosensitive film showed thatflame was extinguished in 4 seconds on average. Thus, the photosensitivefilm passed the UL94V-0 standard. Moreover, development test of thephotosensitive film showed that a fine hole of a square sized 100 μm×100μm was developed successfully. Thus, the photosensitive film got a“pass” in the development test. Further the photosensitive film had aninsulating resistance of 7.0×10¹⁴ Ω in a normal condition, and anadhesion strength of 600 Pa·m. The photosensitive film got a “pass” insoldering heat resistance.

[0816] Moreover, prepared was a flexible copper-clad laminate on whichthe photosensitive film prepared as in the one used in the measurementof the line-to-line insulating resistance was laminated. A resistance ofthe flexible copper-clad laminate on which the photosensitive film waslaminated was measured by applying a DC 100V in a thermo-hygrostat(PL-2FP, made by Tabai Espec Corp.) having a temperature of 85° C. and ahumidity of 85% RH. A measuring apparatus used here was ion migrationevaluation system AMI-025-PL, made by Tabai Espec Corp. With a migrationevaluation system connected with an electrode terminal 1 shown in FIG.2, a change in measurement values was observed. As a result, aresistance of 10¹⁰ Ω or more was maintained for 1,000 hours, whereby thephotosensitive film got a “pass”.

Comparative Example 19

[0817] A photosensitive film/three-layer sheet was prepared in the samemanner as in Example 32, except that 50 parts by weight of a copolymersolution of methacrylate (methylethyl ketone solution of a ternarycopolymer containing methyl methacrylate 57% by weight, methacrylic acid23% by weight, and butyl acrylate 10% by weight: solid content 32%,Mw=85,000) was added instead of the soluble polyimide.

[0818] Flame resistance test of the photosensitive film showed thatflame was combusted with flame. Thus, the photosensitive film failed theUL94V-0 standard. Moreover, development test of the photosensitive filmshowed that a fine hole of a square sized 100 μm×100 μm was developedsuccessfully. Thus, the photosensitive film got a “pass” in thedevelopment test (note that the developer used here was 1% aqueoussolution of sodium carbonate). Further the photosensitive film had aninsulating resistance of 1.0×10¹² Ω in a normal condition, and anadhesion strength of 400 Pa·m. The photosensitive film was swollen andgot a “fail” in soldering heat resistance.

[0819] Moreover, prepared was a flexible copper-clad laminate on whichthe photosensitive film prepared as in the one used in the measurementof the line-to-line insulating resistance was laminated. A resistance ofthe flexible copper-clad laminate on which the photosensitive film waslaminated was measured by applying a DC 100V in a thermo-hygrostat(PL-2FP, made by Tabai Espec Corp.) having a temperature of 85° C. and ahumidity of 85% RH. A measuring apparatus used here was ion migrationevaluation system AMI-025-PL, made by Tabai Espec Corp. With a migrationevaluation system connected with an electrode terminal 1 shown in FIG.2, a change in measurement values was observed. As a result, aresistance of 10¹⁰ Ω was not maintained after 100 hours, whereby thephotosensitive film got a “fail”.

[0820] As described above, a photosensitive resin composition and aphotosensitive film of the present invention have the followingadvantages.

[0821] (1) By containing the (A) soluble polyimide in its composition,the photosensitive resin composition and the photosensitive film of thepresent invention are, after cured, excellent in heat resistance,chemical resistance, electronic insulating property, heat resistance,mechanical properties and the like.

[0822] (2) Especially, by using an imide(meth)acrylate compound as the(B) (meth)acrylic compound, the photosensitive film has, after cured,flame resistance, soldering heat resistance, flexibility, and chemicalresistance.

[0823] (3) Because the (C) photo reaction initiator is used therein, thephotosensitive resin composition and the photosensitive film of thepresent invention have higher photosensitivity and allow drawing of finepatterns thereon.

[0824] (4) Because the halogen compound, phosphorous compound, andsiloxane compound are used as the fire retardant, the photosensitiveresin composition and the photosensitive film of the present inventionrealizes flame resistance, heat resistance and chemical resistance inthe cured film. Especially, by using the phosphorous compound, andsiloxane compound, it is possible to realize the flame resistance thatsatisfies the flame resistance standard UL94V-0 for plastic material,without using a halogen compound as the fire retardant.

[0825] (5) On the whole, the photosensitive resin composition and thephotosensitive film of the present invention are, before being cured,excellent in flowability during the thermal compression bonding and indevelopment property with the alkaline aqueous solution, whereas thephotosensitive resin composition and the photosensitive film of thepresent invention are, after being cured, excellent in flame resistance(flame resistance and self-extinguishing property that satisfy t theflame resistance test standard UL94V-0 for plastic material), heatresistance (soldering heat resistance), chemical resistance(alkaliproof), flexibility, reduction in thickness after imidization,bending resistance (fragility, flexibility), electric insulatingproperty, and mechanical property.

[0826] (6) Therefore, the photosensitive resin composition, thephotosensitive film, and the laminate of the present invention can belaminated on, as a target object, a flexible printed wiring substrate,or a head of a hard disc apparatus, can be used as a cover lay film forthe flexible printed wiring substrate, or the head of the hard discapparatus, and can be used as a permanent photo resist, and the like.

[0827] The invention being thus described, it will be obvious that thesame way may be varied in many ways. Such variations are not to beregarded as a departure from the spirit and scope of the invention, andall such modifications as would be obvious to one skilled in the art areintended to be included within the scope of the following claims.

INDUSTRIAL APPLICABILITY

[0828] As describe above, a photosensitive resin composition, aphotosensitive film, and a laminate of the present invention having suchexcellent property, can be used in the industries for various electronicparts, as well as in the resin industries and chemical industries.Especially, the photosensitive resin composition, the photosensitivefilm, and the laminate of the present invention can be used in anindustry of various printed wiring boards such as flexible printedwiring boards (FPC) and the like, an industry of hard disc apparatusesfor use in personal computers and the like (used as a cover lay film ina head part thereof), and the like industries.

1. A photosensitive resin composition containing a (A) soluble polyimideand a (B) (meth)acrylic compound, the (A) soluble polyimide (i) beingsoluble in an organic solvent and (ii) having at least one of astructural unit represented by Formula (1):

and a structural unit represented by formula (2):

(where, in each formula, R¹ is a tetravalent organic group, R² is adivalent organic group having a siloxane structure or an aromatic ringstructure, R³ is a divalent group having, in its structure, a hydroxylgroup, a carboxyl group, or a carbonyl group), and the (B) (meth)acryliccompound having at least one carbon-carbon double bond.
 2. Thephotosensitive resin composition as set forth in claim 1, containing, asthe (A) soluble polyimide having the structural unit represented byFormula (1), a polyimide having a structural unit represented by Formula(3);

(where R¹¹ is a tetravalent organic group containing an aromatic ringstructure or an alicyclic structure, R²¹ is at least one of a divalentorganic group represented by Formula (4) and a divalent organic grouprepresented by Formula (5):

(where each R²² is independently a divalent hydrocarbon group or adivalent phenyl group, each R²³ is independently an alkyl group having 1to 3 carbon atoms, or a phenyl group, and a is an integer of 3 to 30),and

(where each R²⁴ is independently a hydroxyl group or a carboxyl group,R²⁵ is a direct bond or a divalent organic group selected from the group(6):

(where each R²⁶ is independently a hydrogen atom, a methyl group, or amethyl halide in which 1 to 3 hydrogen atoms are substituded), b is aninteger in a range of 0 to 3, and c is an interger of 1 or 2).
 3. Thephotosensitive resin composition as set forth in claim 2, containing, asthe (A) soluble polyimide having the structural unit represented byFormula (3), a first polymide, a second polyimide and a third polyimide,the first polimide having a recurring unit having a structurerepresented by Formula (7):

(where R¹¹ is identical with R¹¹ in Formula (3), R²² and R²³ areidentical with R²² and R²³ in Formula (4), and a is and integer of 3 to30), the second polyimide having a recurring unit having a structurerepresented by Formula (8):

(where R¹¹ is identical with R¹¹ in Formula (3), R²⁴ and R²⁵ arerespectively identical with R²⁴ and R²⁵ in Formula (5), b is an integerof 0 to 3, and c is an integer of 1 or 2), the third polyimide having astructure in which R²¹ in Formula (3) excludes a siloxane structurerepresented by Formula (4), and an aromatic ring structure representedby Formula (5), wherein a first polyimide content is in a range of 5 mol% to 80 mol %, a second polyimide content is in a range of 0.5 mol % to80 mol %, and third polyimide content is the rest, based on 100 mol % ofthe (A) soluble polyimide; and wherein a log-mean viscosity (0.5 g/100ml) of the photosensitive resin composition is 0.16 or more.
 4. Thephotosensitive resin composition as set forth in claim 1, containing, asthe (A) soluble polyimide having the structural unit represented byFormula (2), a polyimide having a structural unit having a structurerepresented by Formula (9):

(where R¹¹ is identical with R¹¹ in Formula (3), R³⁰ is a divalentorganic group, and R³¹ is a trivalent organic group, and R³² is ahydroxyl group, a carboxyl group, or a monovalent organic group selectedfrom Group (10):

(where R³³ is a functional group that is at least one functional groupselected from the group consisting of an epoxy group, a carbon-carbontriple bond, and carbon-carbon double bond), d is an integer not lessthan 0, and 3 is an integer not less than 1).
 5. The photosensitiveresin composition as set forth in claim 4, wherein: in the (A) solublepolyimide having the structural unit represented by Formula (9), atleast one of R³⁰ and R³¹ in Formula (9) is a structure represented byFormula (11) or Formula (12):

(where R³⁴ is a direct bond, —CH₂—, —C(CH₃)₂—, —C(CF₃)₂—, —O—, —CO—,—COO—, or —SO₂—, each R³⁵ is independently a hydroxyl group, or acarboxyl group, each R³⁶ is independently a hydrogen atom, a hydroxylgroup, a carboxyl group, a halogen atom, a methoxy group, or an alkylgroup having 1 to 5 carbon atoms, f is an integer of 0 to 4, and each gand each h are independently an integer of 0 to 4; and

(where R³⁵ and R³⁶ are respectively identical with R³⁵ and R³⁶ inFormula (11), R³⁷ is a direct bond, —CO—, —O—, —C(CF₃)₂—, —C(CH₃)₂—,—COO—, or —SO₂—, and f, g and h are respectively identical with f, g andh in Formula (11)).
 6. The photosensitive resin composition as set forthin claim 4, wherein: in the (A) soluble polyimide having the structuralunit represented in Formula (9), R³⁰ in Formula (9) is a structurerepresented by Formula (13):

(where each R³⁸ is independently an alkyl group of 1 to 12 carbon atoms,a phenyl group, or a methoxy group, i is an integer of 1 to 5, and j isan integer of 1 to 20).
 7. The photosensitive resin composition as setforth in claim 1, wherein: in the (A) soluble polyimide having thestructural unit represented by Formula (1), R¹ in Formula (1) is atetravalent organic group selected from Group (14):

(where R¹² is a direct bond, —O—, —CH₂—, —CO—, —C(CH₃)₂—, —C(CF₃)₂—,—SO₂, —SO₂— or a divalent organic group, each R¹³ is independently —O—or —COO—, R¹⁴ is a direct bond, —O—, —CH₂—, —CO—, —C(CH₃)₂—,—CH₂—C(CH₃)₂—CH₂—, a straight-chain alkyl group having 1 to 20 carbonatoms, —C(CF₃)₂—, —SO₂, SO₂—, or a divalent organic group, each R¹⁵ isindependently —COO— or —O—, and each R¹⁶ is independently —CH₂—CH₂— or—C₆H₄—C(CH₃)₂—C₆H₄—, or a divalent organic group).
 8. The photosensitiveresin composition as set forth in claim 7, wherein: in the (A) solublepolyimide having the structural unit represented by Formula (1), R¹ inFormula (1) is a tetravalent organic group selected from Group (15):

(where R¹⁷ is any one of a direct bond, —C(CF₃)₂—, —CO—, and —O—, R¹⁸ is—COO— or —O—, R¹⁹ is —CH₂CH₂—, —C₆H₄—C(CH₃)₂—C₆H₄—, or a divalentorganic group), the tetravalent organic group sharing 10 mol % or morein R¹ contained in the (A) soluble polyimide in molar ratio.
 9. Thephotosensitive resin composition as set forth in claim 1, wherein: the(A) soluble polyimide has a boiling point of 120° C. or lower and issoluble in an organic solvent.
 10. The photosensitive resin compositionas set forth in Claim 1, containing, as the (B) (meth)acrylic compoundhaving at least one carbon-carbon double bond: an amide(meth)acrylatecompound having a structure represented by Formula (16) or Formula (18):

(where each R⁴¹ is independently a hydrogen atom or a methyl group, R⁴²is a divalent organic group selected from Group (17):

is a monovalent organic group, m is an integer nd k is an integer notless than 0),

(where each R⁴⁴ is independently a hydrogen atom or a methyl group, andR⁴⁵ is a tetravalent organic group selected from Group (19):

(where each R⁴⁶ and each R⁴⁷ are independently a divalent organic group,and p is an integer of 0 to 5) and n is an interger not less than 0).11. The photosensitive resin composition as set forth in claim 10,further containing, as the (B) (meth)acrylic compound, a (meth)acryliccompound having a structure having no imide ring.
 12. The photosensitiveresin composition as set forth in claim 11, wherein: based on 100% byweight of a total amount of the (A) soluble polyimide and the (B)(meth)acrylic compound, the (A) soluble polyimide is contained in arange of 30% to 70% by weight, and of the (B) (meth)acrylic compound,the imide(meth)acrylate compound is contained in a range of 5% to 60% byweight, and the (meth)acrylic compound having a structure having noimide ring is contained in a range of 1% to 50% by weight.
 13. Thephotosensitive resin composition as set forth in claim 1, furthercontaining: a (C) photo reaction initiator.
 14. The photosensitive resincomposition as set forth in claim 13, wherein: the (C) photo reactioninitiator is a compound that generates a radical by absorbing light of awavelength in a range of 400 nm to 450 nm.
 15. The photosensitive resincomposition as set forth in claim 13, wherein: The (C) photo reactioninitiator is an acylphosphineoxide compound or a combination of3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone and a sensitizer. 16.The photosensitive resin composition as set forth in claim 1, furthercontaining: a (D) fire retardant.
 17. The photosensitive resincomposition as set forth in claim 16, wherein: the (D) fire retardant isat least one of (I) a halogen compound containing a halogen atom in itsstructure, (II) a phosphorous compound containing a phosphorous atom inits structure, and (III) a siloxane containing a siloxane structure inits structure.
 18. The photosensitive resin composition as set forth inclaim 17, wherein: in case where the phosphorous compound is containedas the (D) fire retardant, the phosphorous compound is aphosphorous-nitrogen compound having a 10% weight loss temperature notless than 300° C. and not more than 500° C., and containing aphosphorous atom and a nitrogen atom in its one molecule.
 19. Thephotosensitive resin composition as set forth in claim 18, wherein: thephosphorous-nitrogen compound is at least one kind of compound selectedfrom the group constituting of a phosphazen compound, phosphoricmelamine, polyphosphoric melamine, phosphoric ammonium, andpolyphosphoric ammonium.
 20. The photosensitive resin composition as setforth in claim 18, wherein: the phosphorous-nitrogen compound is aphosphazen compound represented by Formula (20):

(where each R⁵ is independently a hydrogen atom or a monovalent groupcontaining no halogen atom, and q is an integer of 3 to 30).
 21. Thephotosensitive resin composition as set forth in claim 16, wherein: the(A) soluble polyimide is contained in a range of 30% to 70% by weight,the (B) (meth)acrylic compound is contained in a range of 5% to 50% byweight, and the (D) fire retardant is contained in a range of 1% to 50%by weight, based on 100% by weight of a total amount of the (A) solublepolyimide, the (B) (meth)acrylic compound, and the (D) fire retardant.22. The photosensitive resin composition as set forth in claim 18,wherein: in case the phosphorous-nitrogen compound is contained as the(D) fire retardant, the (A) soluble polyimide is contained in a range of30% to 70% by weight, the (B) (meth)acrylic compound is contained in arange of 1% to 50% by weight, and the phosphorous-nitrogen compound iscontained in a range of 10% to 50% by weight, based on 100% by weight ofa total amount of the (A) soluble polyimide, the (B) (meth)acryliccompound, and the phosphorous-nitrogen compound.
 23. The photosensitiveresin composition as set forth in claim 17, wherein: in case thesiloxane compound is contained as the (D) fire retardant, the siloxanecompound is a branched siloxane compound.
 24. The photosensitive resincomposition as set forth in claim 23, wherein: the branched siloxanecompound contains at least one of T unit and Q unit:

(where R⁶ in T unit is a monovalent organic group); and a structuralunit in which R⁶ in the T unit is an aromatic group is contained by 20mol % or more, based on 100 mol % of the T unit.
 25. The photosensitiveresin composition as set forth in claim 24, wherein: in the siloxanecompound containing the T unit, R⁶ in the T unit is a phenyl group. 26.The photosensitive resin composition as set forth in claim 23, wherein:terminal groups of the branched siloxane compound are at least one of avinyl group and a (meth)acrylic group.
 27. The photosensitive resincomposition as set forth in claim 23, wherein: in case the branchedsiloxane is contained as the (D) fire retardant, the (A) solublepolyimide is contained in a range of 30% to 70% by weight, the (B)(meth)acrylic compound is contained in a range of 1% to 50% by weight,and the branched siloxane is contained in a range of 10% to 50% byweight, based on 100% by weight of a total amount of the (A) solublepolyimide, the (B) (meth)acrylic compound, and the branched siloxane.28. The photosensitive resin composition as set forth in claim 1, beingdevelopable with an alkali aqueous solution after being exposed tolight.
 29. The photosensitive resin composition as set forth in claim28, wherein: the alkali aqueous solution contains at least one of acarbonate of an alkali metal, a hydroxide of an alkali metal, and atetraammonium hydroxide.
 30. The photosensitive resin composition as setforth in claim 1, formed in a film-like shape.
 31. The photosensitiveresin composition as set forth in claim 30, being employable as aphotosensitive cover lay film or a photosensitive dry film resist. 32.The photosensitive resin composition as set forth in claim 31, wherein:in case the photosensitive resin composition is formed in the film-likeshape, the photosensitive resin composition satisfies at least one ofproperties (1) to (5): (1) having a curing temperature of 200° C. orless; (2) having a post-curing thermolysis starting temperature of 300°C. or more; (3) having a line-to-line insulating resistance of 10¹³ Ω ormore after 24-hour moisture conditioning at 20° C. and 65% RH; (4) beingcapable of sustaining a resistance of 10¹³ Ω or more for a period of 500hours or longer at application of a direct current of 100V at 85° C. at85% RH, in case where the photosensitive film is applied on acupper-clad board on which a comb-shaped pattern having line/space=100μm/100 μm is formed; and (5) having a soldering heat resistance of 300°C. or more after 48-hour humidity control at 35° C. at 85% RH.
 33. Thephotosensitive resin composition as set forth in claim 31, wherein: incase the photosensitive resin composition is formed in the film-likeshape, the photosensitive resin composition is compression-bondable at150° C. or less onto a target object to which the photosensitive resincomposition is to be laminated.
 34. The photosensitive resin compositionas set forth in claim 33, having, in case the target object is apolyimide film or a copper foil having a glossy surface, acompression-bondable temperature in a range of 20° C. to 150° C. whenthe photosensitive resin composition is in a B stage condition.
 35. Thephotosensitive resin composition as set forth in claim 31, wherein: astickiness strength between the photosensitive resin composition andcopper is the 5 Pa·m or more at 20° C., in case the photosensitive resincomposition is formed in the film-like shape and the target object ismade of copper.
 36. The photosensitive resin composition as set forth inclaim 31, being capable of being laminated on, as the target object, aflexible print wiring substrate or a head of a hard disc apparatus, incase the photosensitive resin composition is formed in the film-likeshape.
 37. A photosensitive film produced by forming a photosensitiveresin composition in a film-like shape, the photosensitive resincomposition containing: a (A) soluble polyimide, a (B) (meth)acryliccompound, and at least one of a (C) photo reaction initiator and asensitizer, the (A) soluble polyimide (i) being soluble in an organicsolvent and (ii) having at least one of a structural unit represented byFormula (1):

and a structural unit represented by Formula (2):

(where, in each formula, R¹ is a tetravalent organic group, R² is adivalent organic group having a siloxane structure or an aromatic ringstructure, R³ is a divalent group having, in its structure, a hydroxylgroup, a carboxyl group, or a carbonyl group), and the (B) (meth)acryliccompound having at least one carbon-carbon double bond).
 38. Thephotosensitive film as set forth in claim 37, wherein: thephotosensitive resin composition further contains a (D) fire retardant,which is at least one of (I) a phosphorous compound containing aphosphorous atom in its structure, and (II) a siloxane containing asiloxane structure in its structure.
 39. The photosensitive film as setforth in claim 37, being employable as a photosensitive cover lay filmor a photosensitive dry film resist.
 40. The photosensitive film as setforth in claim 39, being employable as a flexible print wiring substrateor a cover lay film for a head of a hard disc apparatus.
 41. A laminateincluding a photosensitive layer produced from a photosensitive resincomposition containing a (A) soluble polyimide, a (B) (meth)acryliccompound, and at least one of a (C) photo reaction initiator and asensitizer, the (A) soluble polyimide (i) being soluble in an organicsolvent and (ii) having at least one of a structural unit represented byFormula (1):

and a structural unit represented by Formula (2):

(where, in each formula, R¹ is a tetravalent organic group, R² is adivalent organic group having a siloxane structure or an aromatic ringstructure, R³ is a divalent group having, in its structure, a hydroxylgroup, a carboxyl group, or a carbonyl group), and the (B) (meth)acryliccompound having at least one carbon-carbon double bond).
 42. Thelaminate as set forth in claim 41, being a two-layer sheet formed bylaminating a photosensitive layer on a supporting film, or a three-layersheet formed by laminating a photosensitive layer on a supporting filmand further laminating a protective film on the photosensitive layer.43. The laminate as set forth in claim 42, wherein: the photosensitivelayer is produced by applying, on the supporting film, a resincomposition solution, and then drying the resin composition solution onthe supporting film, the resin composition solution prepared bydissolving the photosensitive resin composition in an organic solvent.